The Variation of Animals and Plants under Domestication
by Charles Darwin M.A., F.R.S., ETC.
VOLUMES ONE AND TWO
CONTENTS.
FOREWORD
PREFACE TO THE SECOND EDITION
INTRODUCTION
CHAPTER I.—DOMESTIC DOGS AND CATS.
ANCIENT VARIETIES OF THE DOG—RESEMBLANCE OF DOMESTIC DOGS IN VARIOUS
COUNTRIES TO NATIVE CANINE SPECIES—ANIMALS NOT ACQUAINTED WITH MAN AT
FIRST FEARLESS—DOGS RESEMBLING WOLVES AND JACKALS—HABIT OF BARKING
ACQUIRED AND LOST—FERAL DOGS—TAN-COLOURED EYE-SPOTS—PERIOD OF
GESTATION—OFFENSIVE ODOUR—FERTILITY OF THE RACES WHEN
CROSSED—DIFFERENCES IN THE SEVERAL RACES IN PART DUE TO DESCENT FROM
DISTINCT SPECIES—DIFFERENCES IN THE SKULL AND TEETH—DIFFERENCES IN THE
BODY, IN CONSTITUTION—FEW IMPORTANT DIFFERENCES HAVE BEEN FIXED BY
SELECTION—DIRECT ACTION OF CLIMATE—WATER-DOGS WITH PALMATED
FEET—HISTORY OF THE CHANGES WHICH CERTAIN ENGLISH RACES OF THE DOG HAVE
GRADUALLY UNDERGONE THROUGH SELECTION—EXTINCTION OF THE LESS IMPROVED
SUB-BREEDS.
CATS, CROSSED WITH SEVERAL SPECIES—DIFFERENT BREEDS FOUND ONLY IN
SEPARATED COUNTRIES—DIRECT EFFECTS OF THE CONDITIONS OF LIFE—FERAL
CATS—INDIVIDUAL VARIABILITY.
CHAPTER II.—HORSES AND ASSES.
HORSE. DIFFERENCES IN THE BREEDS—INDIVIDUAL VARIABILITY OF—DIRECT
EFFECTS OF THE CONDITIONS OF LIFE—CAN WITHSTAND MUCH COLD—BREEDS MUCH
MODIFIED BY SELECTION—COLOURS OF THE HORSE—DAPPLING—DARK STRIPES ON THE
SPINE, LEGS, SHOULDERS, AND FOREHEAD—DUN-COLOURED HORSES MOST
FREQUENTLY STRIPED—STRIPES PROBABLY DUE TO REVERSION TO THE PRIMITIVE
STATE OF THE HORSE.
ASSES. BREEDS OF—COLOUR OF—LEG- AND SHOULDER-STRIPES—SHOULDER-STRIPES
SOMETIMES ABSENT, SOMETIMES FORKED.
CHAPTER III.—PIGS—CATTLE—SHEEP—GOATS.
PIGS BELONG TO TWO DISTINCT TYPES, SUS SCROFA AND
INDICUS—TORFSCHWEIN—JAPAN PIGS—FERTILITY OF CROSSED PIGS—CHANGES IN THE
SKULL OF THE HIGHLY CULTIVATED RACES—CONVERGENCE OF
CHARACTER—GESTATION—SOLID-HOOFED SWINE—CURIOUS APPENDAGES TO THE
JAWS—DECREASE IN SIZE OF THE TUSKS—YOUNG PIGS LONGITUDINALLY
STRIPED—FERAL PIGS—CROSSED BREEDS.
CATTLE—ZEBU A DISTINCT SPECIES—EUROPEAN CATTLE PROBABLY DESCENDED FROM
THREE WILD FORMS—ALL THE RACES NOW FERTILE TOGETHER—BRITISH PARK
CATTLE—ON THE COLOUR OF THE ABORIGINAL SPECIES—CONSTITUTIONAL
DIFFERENCES—SOUTH AFRICAN RACES—SOUTH AMERICAN RACES—NIATA
CATTLE—ORIGIN OF THE VARIOUS RACES OF CATTLE.
SHEEP —REMARKABLE RACES OF—VARIATIONS ATTACHED TO THE MALE
SEX—ADAPTATIONS TO VARIOUS CONDITIONS—GESTATION OF—CHANGES IN THE
WOOL—SEMI-MONSTROUS BREEDS.
GOATS —REMARKABLE VARIATIONS OF.
CHAPTER IV.—DOMESTIC RABBITS.
DOMESTIC RABBITS DESCENDED FROM THE COMMON WILD RABBIT—ANCIENT
DOMESTICATION—ANCIENT SELECTION—LARGE LOP-EARED RABBITS—VARIOUS
BREEDS—FLUCTUATING CHARACTERS—ORIGIN OF THE HIMALAYAN BREED—CURIOUS
CASE OF INHERITANCE—FERAL RABBITS IN JAMAICA AND THE FALKLAND
ISLANDS—PORTO SANTO FERAL RABBITS—OSTEOLOGICAL CHARACTERS—SKULL—SKULL
OF HALF-LOP RABBITS—VARIATIONS IN THE SKULL ANALOGOUS TO DIFFERENCES IN
DIFFERENT SPECIES OF HARES—VERtebræ—STERNUM—SCAPULA—EFFECTS OF USE AND
DISUSE ON THE PROPORTIONS OF THE LIMBS AND BODY—CAPACITY OF THE SKULL
AND REDUCED SIZE OF THE BRAIN—SUMMARY ON THE MODIFICATIONS OF
DOMESTICATED RABBITS.
CHAPTER V.—DOMESTIC PIGEONS.
ENUMERATION AND DESCRIPTION OF THE SEVERAL BREEDS—INDIVIDUAL
VARIABILITY—VARIATIONS OF A REMARKABLE NATURE—OSTEOLOGICAL CHARACTERS:
SKULL, LOWER JAW, NUMBER OF vertebræ—CORRELATION OF GROWTH: TONGUE WITH
BEAK; EYELIDS AND NOSTRILS WITH WATTLED SKIN—NUMBER OF WING-FEATHERS,
AND LENGTH OF WING—COLOUR AND DOWN—WEBBED AND FEATHERED FEET—ON THE
EFFECTS OF DISUSE—LENGTH OF FEET IN CORRELATION WITH LENGTH OF
BEAK—LENGTH OF STERNUM, SCAPULA, AND FURCULUM—LENGTH OF WINGS—SUMMARY
ON THE POINTS OF DIFFERENCE IN THE SEVERAL BREEDS.
CHAPTER VI.—PIGEONS—_continued._
ON THE ABORIGINAL PARENT-STOCK OF THE SEVERAL DOMESTIC RACES—HABITS OF
LIFE—WILD RACES OF THE ROCK-PIGEON—Dovecot-PIGEONS—PROOFS OF THE
DESCENT OF THE SEVERAL RACES FROM COLUMBA LIVIA—FERTILITY OF THE RACES
WHEN CROSSED—REVERSION TO THE PLUMAGE OF THE WILD
ROCK-PIGEON—CIRCUMSTANCES FAVOURABLE TO THE FORMATION OF THE
RACES—ANTIQUITY AND HISTORY OF THE PRINCIPAL RACES—MANNER OF THEIR
FORMATION—SELECTION—UNCONSCIOUS SELECTION—CARE TAKEN BY FANCIERS IN
SELECTING THEIR BIRDS—SLIGHTLY DIFFERENT STRAINS GRADUALLY CHANGE INTO
WELL-MARKED BREEDS—EXTINCTION OF INTERMEDIATE FORMS—CERTAIN BREEDS
REMAIN PERMANENT, WHILST OTHERS CHANGE—SUMMARY.
CHAPTER VII.—FOWLS.
BRIEF DESCRIPTIONS OF THE CHIEF BREEDS—ARGUMENTS IN FAVOUR OF THEIR
DESCENT FROM SEVERAL SPECIES—ARGUMENTS IN FAVOUR OF ALL THE BREEDS
HAVING DESCENDED FROM GALLUS BANKIVA—REVERSION TO THE PARENT-STOCK IN
COLOUR—ANALOGOUS VARIATIONS—ANCIENT HISTORY OF THE FOWL—EXTERNAL
DIFFERENCES BETWEEN THE SEVERAL BREEDS—EGGS—CHICKENS—SECONDARY SEXUAL
CHARACTERS—WING-AND TAIL-FEATHERS, VOICE, DISPOSITION, ETC—OSTEOLOGICAL
DIFFERENCES IN THE SKULL, VERTEBRÆ, ETC—EFFECTS OF USE AND DISUSE ON
CERTAIN PARTS—CORRELATION OF GROWTH.
CHAPTER
VIII.—DUCK—GOOSE—PEACOCK—TURKEY—GUINEA-FOWL—CANARY-BIRD—GOLD-FISH—RIVER
-BEES—SILK-MOTHS.
DUCKS, SEVERAL BREEDS OF—PROGRESS OF DOMESTICATION—ORIGIN OF FROM THE
COMMON WILD-DUCK—DIFFERENCES IN THE DIFFERENT BREEDS—OSTEOLOGICAL
DIFFERENCES—EFFECTS OF USE AND DISUSE ON THE LIMB-BONES.
GOOSE, ANCIENTLY DOMESTICATED—LITTLE VARIATION OF—SEBASTOPOL BREED.
PEACOCK, ORIGIN OF BLACK-SHOULDERED BREED.
TURKEY,BREEDS OF—CROSSED WITH THE UNITED STATES SPECIES—EFFECTS OF
CLIMATE ON.
GUINEA-FOWL, CANARY-BIRD, GOLD-FISH, HIVE-BEES.
SILK-MOTHS, SPECIES AND BREEDS OF—ANCIENTLY DOMESTICATED—CARE IN THEIR
SELECTION—DIFFERENCES IN THE DIFFERENT RACES—IN THE EGG, CATERPILLAR,
AND COCOON STATES—INHERITANCE OF CHARACTERS—IMPERFECT WINGS—LOST
INSTINCTS—CORRELATED CHARACTERS.
CHAPTER IX.—CULTIVATED PLANTS: CEREAL AND CULINARY PLANTS.
PRELIMINARY REMARKS ON THE NUMBER AND PARENTAGE OF CULTIVATED
PLANTS—FIRST STEPS IN CULTIVATION—GEOGRAPHICAL DISTRIBUTION OF
CULTIVATED PLANTS.
CEREALIA. DOUBTS ON THE NUMBER OF SPECIES—WHEAT: VARIETIES
OF—INDIVIDUAL VARIABILITY—CHANGED HABITS—SELECTION—ANCIENT HISTORY OF
THE VARIETIES—MAIZE: GREAT VARIATION OF—DIRECT ACTION OF CLIMATE ON.
CULINARY PLANTS.—CABBAGES: VARIETIES OF, IN FOLIAGE AND STEMS, BUT NOT
IN OTHER PARTS—PARENTAGE OF—OTHER SPECIES OF BRASSICA—PEAS: AMOUNT OF
DIFFERENCE IN THE SEVERAL KINDS, CHIEFLY IN THE PODS AND SEED—SOME
VARIETIES CONSTANT, SOME HIGHLY VARIABLE—DO NOT
INTERCROSS—BEANS—POTATOES: NUMEROUS VARIETIES OF—DIFFERING LITTLE
EXCEPT IN THE TUBERS—CHARACTERS INHERITED.
CHAPTER X.—PLANTS _continued_—FRUITS—ORNAMENTAL TREES—FLOWERS.
FRUITS. GRAPES: VARY IN ODD AND TRIFLING PARTICULARS—MULBERRY: THE
ORANGE GROUP—SINGULAR RESULTS FROM CROSSING— PEACH AND NECTARINE: BUD
VARIATION—ANALOGOUS VARIATION—RELATION TO THE ALMOND—APRICOT—PLUMS:
VARIATION IN THEIR STONES— CHERRIES: SINGULAR VARIETIES
OF—APPLE—PEAR—STRAWBERRY: INTERBLENDING OF THE ORIGINAL
FORMS—GOOSEBERRY: STEADY INCREASE IN SIZE OF THE FRUIT—VARIETIES
OF—WALNUT—NUT—CUCURBITACEOUS PLANTS: WONDERFUL VARIATION OF.
ORNAMENTAL TREES. THEIR VARIATION IN DEGREE AND
KIND—ASH-TREE—SCOTCH-FIR—HAWTHORN.
FLOWERS. MULTIPLE ORIGIN OF MANY KINDS—VARIATION IN CONSTITUTIONAL
PECULIARITIES—KIND OF VARIATION—ROSES: SEVERAL SPECIES
CULTIVATED—PANSY—DAHLIA—HYACINTH: HISTORY AND VARIATION OF.
CHAPTER XI.—ON BUD-VARIATION, AND ON CERTAIN ANOMALOUS MODES OF
REPRODUCTION AND VARIATION.
BUD-VARIATION IN THE PEACH, PLUM, CHERRY, VINE, GOOSEBERRY, CURRANT,
AND BANANA, AS SHOWN BY THE MODIFIED FRUIT—IN FLOWERS: CAMELLIAS,
AZALEAS, CHRYSANTHEMUMS, ROSES, ETC—ON THE RUNNING OF THE COLOUR IN
CARNATIONS—BUD-VARIATIONS IN LEAVES—VARIATIONS BY SUCKERS, TUBERS, AND
BULBS—ON THE BREAKING OF TULIPS—BUD-VARIATIONS GRADUATE INTO CHANGES
CONSEQUENT ON CHANGED CONDITIONS OF LIFE—GRAFT-HYBRIDS—ON THE
SEGREGATION OF THE PARENTAL CHARACTERS IN SEMINAL HYBRIDS BY
BUD-VARIATION—ON THE DIRECT OR IMMEDIATE ACTION OF FOREIGN POLLEN ON
THE MOTHER-PLANT—ON THE EFFECTS IN FEMALE ANIMALS OF A PREVIOUS
IMPREGNATION ON THE SUBSEQUENT OFFSPRING—CONCLUSION AND SUMMARY.
CHAPTER XII.—INHERITANCE.
WONDERFUL NATURE OF INHERITANCE—PEDIGREES OF OUR DOMESTICATED
ANIMALS—INHERITANCE NOT DUE TO CHANCE—TRIFLING CHARACTERS
INHERITED—DISEASES INHERITED—PECULIARITIES IN THE EYE
INHERITED—DISEASES IN THE HORSE—LONGEVITY AND VIGOUR—ASYMMETRICAL
DEVIATIONS OF STRUCTURE—POLYDACTYLISM AND REGROWTH OF SUPERNUMERARY
DIGITS AFTER AMPUTATION—CASES OF SEVERAL CHILDREN SIMILARLY AFFECTED
FROM NON-AFFECTED PARENTS—WEAK AND FLUCTUATING INHERITANCE: IN WEEPING
TREES, IN DWARFNESS, COLOUR OF FRUIT AND FLOWERS—COLOUR OF
HORSES—NON-INHERITANCE IN CERTAIN CASES—INHERITANCE OF STRUCTURE AND
HABITS OVERBORNE BY HOSTILE CONDITIONS OF LIFE, BY INCESSANTLY
RECURRING VARIABILITY, AND BY REVERSION—CONCLUSION.
CHAPTER XIII.—INHERITANCE _continued_—REVERSION OF ATAVISM.
DIFFERENT FORMS OF REVERSION—IN PURE OR UNCROSSED BREEDS, AS IN
PIGEONS, FOWLS, HORNLESS CATTLE AND SHEEP, IN CULTIVATED
PLANTS—REVERSION IN FERAL ANIMALS AND PLANTS—REVERSION IN CROSSED
VARIETIES AND SPECIES—REVERSION THROUGH BUD-PROPAGATION, AND BY
SEGMENTS IN THE SAME FLOWER OR FRUIT—IN DIFFERENT PARTS OF THE BODY IN
THE SAME ANIMAL—THE ACT OF CROSSING A DIRECT CAUSE OF REVERSION,
VARIOUS CASES OF, WITH INSTINCTS—OTHER PROXIMATE CAUSES OF
REVERSION—LATENT CHARACTERS—SECONDARY SEXUAL CHARACTERS—UNEQUAL
DEVELOPMENT OF THE TWO SIDES OF THE BODY—APPEARANCE WITH ADVANCING AGE
OF CHARACTERS DERIVED FROM A CROSS—THE GERM, WITH ALL ITS LATENT
CHARACTERS, A WONDERFUL OBJECT—MONSTROSITIES—PELORIC FLOWERS DUE IN
SOME CASES TO REVERSION.
CHAPTER XIV.—INHERITANCE _continued_—FIXEDNESS OF
CHARACTER—PREPOTENCY—SEXUAL LIMITATION—CORRESPONDENCE OF AGE.
FIXEDNESS OF CHARACTER APPARENTLY NOT DUE TO ANTIQUITY OF
INITANCE—PREPOTENCY OF TRANSMISSION IN INDIVIDUALS OF THE SAME FAMILY,
IN CROSSED BREEDS AND SPECIES; OFTEN STRONGER IN ONE SEX THAN THE
OTHER; SOMETIMES DUE TO THE SAME CHARACTER BEING PRESENT AND VISIBLE IN
ONE BREED AND LATENT IN THE OTHER—INHERITANCE AS LIMITED BY
SEX—NEWLY-ACQUIRED CHARACTERS IN OUR DOMESTICATED ANIMALS OFTEN
TRANSMITTED BY ONE SEX ALONE, SOMETIMES LOST BY ONE SEX
ALONE—INHERITANCE AT CORRESPONDING PERIODS OF LIFE—THE IMPORTANCE OF
THE PRINCIPLE WITH RESPECT TO EMBRYOLOGY; AS EXHIBITED IN DOMESTICATED
ANIMALS: AS EXHIBITED IN THE APPEARANCE AND DISAPPEARANCE OF INHERITED
DISEASES; SOMETIMES SUPERVENING EARLIER IN THE CHILD THAN IN THE
PARENT—SUMMARY OF THE THREE PRECEDING CHAPTERS.
CHAPTER XV.—ON CROSSING.
FREE INTERCROSSING OBLITERATES THE DIFFERENCES BETWEEN ALLIED
BREEDS—WHEN THE NUMBERS OF TWO COMMINGLING BREEDS ARE UNEQUAL, ONE
ABSORBS THE OTHER—THE RATE OF ABSORPTION DETERMINED BY PREPOTENCY OF
TRANSMISSION, BY THE CONDITIONS OF LIFE, AND BY NATURAL SELECTION—ALL
ORGANIC BEINGS OCCASIONALLY INTERCROSS; APPARENT EXCEPTIONS—ON CERTAIN
CHARACTERS INCAPABLE OF FUSION; CHIEFLY OR EXCLUSIVELY THOSE WHICH HAVE
SUDDENLY APPEARED IN THE INDIVIDUAL—ON THE MODIFICATION OF OLD RACES,
AND THE FORMATION OF NEW RACES BY CROSSING—SOME CROSSED RACES HAVE BRED
TRUE FROM THEIR FIRST PRODUCTION—ON THE CROSSING OF DISTINCT SPECIES IN
RELATION TO THE FORMATION OF DOMESTIC RACES.
CHAPTER XVI.—CAUSES WHICH INTERFERE WITH THE FREE CROSSING OF
VARIETIES—INFLUENCE OF DOMESTICATION ON FERTILITY.
DIFFICULTIES IN JUDGING OF THE FERTILITY OF VARIETIES WHEN CROSSED.
VARIOUS CAUSES WHICH KEEP VARIETIES DISTINCT, AS THE PERIOD OF BREEDING
AND SEXUAL PREFERENCE—VARIETIES OF WHEAT SAID TO BE STERILE WHEN
CROSSED—VARIETIES OF MAIZE, VERBASCUM, HOLLYHOCK, GOURDS, MELONS, AND
TOBACCO, RENDERED IN SOME DEGREE MUTUALLY STERILE—DOMESTICATION
ELIMINATES THE TENDENCY TO STERILITY NATURAL TO SPECIES WHEN CROSSED—ON
THE INCREASED FERTILITY OF UNCROSSED ANIMALS AND PLANTS FROM
DOMESTICATION AND CULTIVATION.
CHAPTER XVII.—ON THE GOOD EFFECTS OF CROSSING, AND ON THE EVIL EFFECTS
OF CLOSE INTERBREEDING.
DEFINITION OF CLOSE INTERBREEDING—AUGMENTATION OF MORBID
TENDENCIES—GENERAL EVIDENCE OF THE GOOD EFFECTS DERIVED FROM CROSSING,
AND ON THE EVIL EFFECTS FROM CLOSE INTERBREEDING—CATTLE, CLOSELY
INTERBRED; HALF-WILD CATTLE LONG KEPT IN THE SAME
PARKS—SHEEP—FALLOW-DEER—DOGS, RABBITS, PIGS—MAN, ORIGIN OF HIS
ABHORRENCE OF INCESTUOUS MARRIAGES—FOWLS—PIGEONS—HIVE-BEES—PLANTS,
GENERAL CONSIDERATIONS ON THE BENEFITS DERIVED FROM CROSSING—MELONS,
FRUIT-TREES, PEAS, CABBAGES, WHEAT, AND FOREST-TREES—ON THE INCREASED
SIZE OF HYBRID PLANTS, NOT EXCLUSIVELY DUE TO THEIR STERILITY—ON
CERTAIN PLANTS WHICH EITHER NORMALLY OR ABNORMALLY ARE SELF-IMPOTENT,
BUT ARE FERTILE, BOTH ON THE MALE AND FEMALE SIDE, WHEN CROSSED WITH
DISTINCT INDIVIDUALS EITHER OF THE SAME OR ANOTHER SPECIES—CONCLUSION.
CHAPTER XVIII.—ON THE ADVANTAGES AND DISADVANTAGES OF CHANGED
CONDITIONS OF LIFE: STERILITY FROM VARIOUS CAUSES.
ON THE GOOD DERIVED FROM SLIGHT CHANGES IN THE CONDITIONS OF
LIFE—STERILITY FROM CHANGED CONDITIONS, IN ANIMALS, IN THEIR NATIVE
COUNTRY AND IN MENAGERIES—MAMMALS, BIRDS, AND INSECTS—LOSS OF SECONDARY
SEXUAL CHARACTERS AND OF INSTINCTS—CAUSES OF STERILITY—STERILITY OF
DOMESTICATED ANIMALS FROM CHANGED CONDITIONS—SEXUAL INCOMPATIBILITY OF
INDIVIDUAL ANIMALS—STERILITY OF PLANTS FROM CHANGED CONDITIONS OF
LIFE—CONTABESCENCE OF THE ANTHERS—MONSTROSITIES AS A CAUSE OF
STERILITY—DOUBLE FLOWERS—SEEDLESS FRUIT—STERILITY FROM THE EXCESSIVE
DEVELOPMENT OF THE ORGANS OF VEGETATION—FROM LONG-CONTINUED PROPAGATION
BY BUDS—INCIPIENT STERILITY THE PRIMARY CAUSE OF DOUBLE FLOWERS AND
SEEDLESS FRUIT.
CHAPTER XIX.—SUMMARY OF THE FOUR LAST CHAPTERS, WITH REMARKS ON
HYBRIDISM.
ON THE GOOD DERIVED ON THE EFFECTS OF CROSSING—THE INFLUENCE OF
DOMESTICATION ON FERTILITY—CLOSE INTERBREEDING—GOOD AND EVIL RESULTS
FROM CHANGED CONDITIONS OF LIFE—VARIETIES WHEN CROSSED NOT INVARIABLY
FERTILE—ON THE DIFFERENCE IN FERTILITY BETWEEN CROSSED SPECIES AND
VARIETIES—CONCLUSIONS WITH RESPECT TO HYBRIDISM—LIGHT THROWN ON
HYBRIDISM BY THE ILLEGITIMATE PROGENY OF HETEROSTYLED PLANTS—STERILITY
OF CROSSED SPECIES DUE TO DIFFERENCES CONFINED TO THE REPRODUCTIVE
SYSTEM—NOT ACCUMULATED THROUGH NATURAL SELECTION—REASONS WHY DOMESTIC
VARIETIES ARE NOT MUTUALLY STERILE—TOO MUCH STRESS HAS BEEN LAID ON THE
DIFFERENCE IN FERTILITY BETWEEN CROSSED SPECIES AND CROSSED
VARIETIES—CONCLUSION.
CHAPTER XX.—SELECTION BY MAN.
SELECTION A DIFFICULT ART—METHODICAL, UNCONSCIOUS, AND NATURAL
SELECTION—RESULTS OF METHODICAL SELECTION—CARE TAKEN IN
SELECTION—SELECTION WITH PLANTS—SELECTION CARRIED ON BY THE ANCIENTS
AND BY SEMI-CIVILISED PEOPLE—UNIMPORTANT CHARACTERS OFTEN ATTENDED
TO—UNCONSCIOUS SELECTION—AS CIRCUMSTANCES SLOWLY CHANGE, SO HAVE OUR
DOMESTICATED ANIMALS CHANGED THROUGH THE ACTION OF UNCONSCIOUS
SELECTION—INFLUENCE OF DIFFERENT BREEDERS ON THE SAME
SUB-VARIETY—PLANTS AS AFFECTED BY UNCONSCIOUS SELECTION—EFFECTS OF
SELECTION AS SHOWN BY THE GREAT AMOUNT OF DIFFERENCE IN THE PARTS MOST
VALUED BY MAN.
CHAPTER XXI.—SELECTION, _continued_
NATURAL SELECTION AS AFFECTING DOMESTIC PRODUCTIONS—CHARACTERS WHICH
APPEAR OF TRIFLING VALUE OFTEN OF REAL IMPORTANCE—CIRCUMSTANCES
FAVOURABLE TO SELECTION BY MAN—FACILITY IN PREVENTING CROSSES, AND THE
NATURE OF THE CONDITIONS—CLOSE ATTENTION AND PERSEVERANCE
INDISPENSABLE—THE PRODUCTION OF A LARGE NUMBER OF INDIVIDUALS
ESPECIALLY FAVOURABLE—WHEN NO SELECTION IS APPLIED, DISTINCT RACES ARE
NOT FORMED—HIGHLY-BRED ANIMALS LIABLE TO DEGENERATION—TENDENCY IN MAN
TO CARRY THE SELECTION OF EACH CHARACTER TO AN EXTREME POINT, LEADING
TO DIVERGENCE OF CHARACTER, RARELY TO CONVERGENCE—CHARACTERS CONTINUING
TO VARY IN THE SAME DIRECTION IN WHICH THEY HAVE ALREADY
VARIED—DIVERGENCE OF CHARACTER, WITH THE EXTINCTION OF INTERMEDIATE
VARIETIES, LEADS TO DISTINCTNESS IN OUR DOMESTIC RACES—LIMIT TO THE
POWER OF SELECTION—LAPSE OF TIME IMPORTANT—MANNER IN WHICH DOMESTIC
RACES HAVE ORIGINATED—SUMMARY.
CHAPTER XXII.—CAUSES OF VARIABILITY.
VARIABILITY DOES NOT NECESSARILY ACCOMPANY REPRODUCTION—CAUSES ASSIGNED
BY VARIOUS AUTHORS—INDIVIDUAL DIFFERENCES—VARIABILITY OF EVERY KIND DUE
TO CHANGED CONDITIONS OF LIFE—ON THE NATURE OF SUCH CHANGES—CLIMATE,
FOOD, EXCESS OF NUTRIMENT—SLIGHT CHANGES SUFFICIENT—EFFECTS OF GRAFTING
ON THE VARIABILITY OF SEEDLING-TREES—DOMESTIC PRODUCTIONS BECOME
HABITUATED TO CHANGED CONDITIONS—ON THE ACCUMULATIVE ACTION OF CHANGED
CONDITIONS—CLOSE INTERBREEDING AND THE IMAGINATION OF THE MOTHER
SUPPOSED TO CAUSE VARIABILITY—CROSSING AS A CAUSE OF THE APPEARANCE OF
NEW CHARACTERS—VARIABILITY FROM THE COMMINGLING OF CHARACTERS AND FROM
REVERSION—ON THE MANNER AND PERIOD OF ACTION OF THE CAUSES WHICH EITHER
DIRECTLY, OR INDIRECTLY THROUGH THE REPRODUCTIVE SYSTEM, INDUCE
VARIABILITY.
CHAPTER XXIII.—DIRECT AND DEFINITE ACTION OF THE EXTERNAL CONDITIONS OF
LIFE.
SLIGHT MODIFICATIONS IN PLANTS FROM THE DEFINITE ACTION OF CHANGED
CONDITIONS, IN SIZE, COLOUR, CHEMICAL PROPERTIES, AND IN THE STATE OF
THE TISSUES—LOCAL DISEASES—CONSPICUOUS MODIFICATIONS FROM CHANGED
CLIMATE OR FOOD, ETC—PLUMAGE OF BIRDS AFFECTED BY PECULIAR NUTRIMENT,
AND BY THE INOCULATION OF POISON—LAND-SHELLS—MODIFICATIONS OF ORGANIC
BEINGS IN A STATE OF NATURE THROUGH THE DEFINITE ACTION OF EXTERNAL
CONDITIONS—COMPARISON OF AMERICAN AND EUROPEAN TREES—GALLS—EFFECTS OF
PARASITIC FUNGI—CONSIDERATIONS OPPOSED TO THE BELIEF IN THE POTENT
INFLUENCE OF CHANGED EXTERNAL CONDITIONS—PARALLEL SERIES OF
VARIETIES—AMOUNT OF VARIATION DOES NOT CORRESPOND WITH THE DEGREE OF
CHANGE IN THE CONDITIONS—BUD-VARIATION—MONSTROSITIES PRODUCED BY
UNNATURAL TREATMENT—SUMMARY.
CHAPTER XXIV.—LAWS OF VARIATION—USE AND DISUSE, ETC.
NISUS FORMATIVUS, OR THE CO-ORDINATING POWER OF THE ORGANISATION—ON THE
EFFECTS OF THE INCREASED USE AND DISUSE OF ORGANS—CHANGED HABITS OF
LIFE—ACCLIMATISATION WITH ANIMALS AND PLANTS—VARIOUS METHODS BY WHICH
THIS CAN BE EFFECTED—ARRESTS OF DEVELOPMENT—RUDIMENTARY ORGANS.
CHAPTER XXV.—LAWS OF VARIATION, _continued._—CORRELATED VARIABILITY.
EXPLANATION OF TERM CORRELATION—CONNECTED WITH
DEVELOPMENT—MODIFICATIONS CORRELATED WITH THE INCREASED OR DECREASED
SIZE OF PARTS—CORRELATED VARIATION OF HOMOLOGOUS PARTS—FEATHERED FEET
IN BIRDS ASSUMING THE STRUCTURE OF THE WINGS—CORRELATION BETWEEN THE
HEAD AND THE EXTREMITIES—BETWEEN THE SKIN AND DERMAL APPENDAGES—BETWEEN
THE ORGANS OF SIGHT AND HEARING—CORRELATED MODIFICATIONS IN THE ORGANS
OF PLANTS—CORRELATED MONSTROSITIES—CORRELATION BETWEEN THE SKULL AND
EARS—SKULL AND CREST OF FEATHERS—SKULL AND HORNS—CORRELATION OF GROWTH
COMPLICATED BY THE ACCUMULATED EFFECTS OF NATURAL SELECTION—COLOUR AS
CORRELATED WITH CONSTITUTIONAL PECULIARITIES.
CHAPTER XXVI.—LAWS OF VARIATION, _continued._—SUMMARY.
THE FUSION OF HOMOLOGOUS PARTS—THE VARIABILITY OF MULTIPLE AND
HOMOLOGOUS PARTS—COMPENSATION OF GROWTH—MECHANICAL PRESSURE—RELATIVE
POSITION OF FLOWERS WITH RESPECT TO THE AXIS, AND OF SEEDS IN THE
OVARY, AS INDUCING VARIATION—ANALOGOUS OR PARALLEL VARIETIES—SUMMARY OF
THE THREE LAST CHAPTERS.
CHAPTER XXVII.—PROVISIONAL HYPOTHESIS OF PANGENESIS.
PRELIMINARY REMARKS—FIRST PART: THE FACTS TO BE CONNECTED UNDER A
SINGLE POINT OF VIEW, NAMELY, THE VARIOUS KINDS OF
REPRODUCTION—RE-GROWTH OF AMPUTATED PARTS—GRAFT-HYBRIDS—THE DIRECT
ACTION OF THE MALE ELEMENT ON THE FEMALE—DEVELOPMENT—THE FUNCTIONAL
INDEPENDENCE OF THE UNITS OF THE
BODY—VARIABILITY—INHERITANCE—REVERSION—SECOND PART: STATEMENT OF THE
HYPOTHESIS—HOW FAR THE NECESSARY ASSUMPTIONS ARE IMPROBABLE—EXPLANATION
BY AID OF THE HYPOTHESIS OF THE SEVERAL CLASSES OF FACTS SPECIFIED IN
THE FIRST PART—CONCLUSION.
CHAPTER XXVIII.—CONCLUDING REMARKS.
DOMESTICATION—NATURE AND CAUSES OF VARIABILITY—SELECTION—DIVERGENCE AND
DISTINCTNESS OF CHARACTER—EXTINCTION OF RACES—CIRCUMSTANCES FAVOURABLE
TO SELECTION BY MAN—ANTIQUITY OF CERTAIN RACES—THE QUESTION WHETHER
EACH PARTICULAR VARIATION HAS BEEN SPECIALLY PREORDAINED.
INDEX
LIST OF ILLUSTRATIONS
Figure 1. Dun Devonshire pony, with shoulder, spinal, and leg stripes.
Figure 2. Head of Japan or masked pig.
Figure 3. Head of wild boar, and of “golden days,” a pig of the Yorkshire large breed.
Figure 4. Old Irish pig with jaw-appendages.
Figure 5. Half-lop rabbit.
Figure 6. Skull of wild rabbit.
Figure 7. Skull of large lop-eared rabbit.
Figure 8. Part of zygomatic arch, showing the projecting end of the malar bone of the auditory meatus, of rabbits.
Figure 9. Posterior end of skull, showing the inter-parietal bone, of rabbits.
Figure 10. Occipital foramen of rabbits.
Figure 11. Skull of half-lop rabbit.
Figure 12. Atlas vertebrae of rabbits.
Figure 13. Third cervical vertebrae of rabbits.
Figure 14. Dorsal vertebrae, from sixth to tenth inclusive, of rabbits.
Figure 15. Terminal bone of sternum of rabbits.
Figure 16. Acromion of scapula of rabbits.
Figure 17. The rock-pigeon, or columba livia.
Figure 18. English pouter.
Figure 19. English carrier.
Figure 20. English barb.
Figure 21. English fantail.
Figure 22. African owl.
Figure 23. Short-faced English tumbler.
Figure 24. Skulls of pigeons, viewed laterally.
Figure 25. Lower jaws of pigeons, seen from above.
Figure 26. Skull of runt, seen from above.
Figure 27. Lateral view of jaws of pigeons.
Figure 28. Scapulæ of pigeons.
Figure 29. Furcula of pigeons.
Figure 30. Spanish fowl.
Figure 31. Hamburgh fowl.
Figure 32. Polish fowl.
Figure 33. Occipital foramen of the skulls of fowls.
Figure 34. Skulls of fowls, viewed from above, a little obliquely.
Figure 35. Longitudinal sections of skulls of fowls, viewed laterally.
Figure 36. Skull of horned fowl, viewed from above, a little obliquely.
Figure 37. Sixth cervical vertebræ of fowls, viewed laterally.
Figure 38. Extremity of the furcula of fowls, viewed laterally.
Figure 39. Skulls of ducks, viewed laterally, reduced to two-thirds of the natural size.
Figure 40. Cervical vertebræ of ducks, of natural size.
Figure 41. Pods of the common pea.
Figure 42. Peach and almond stones, of natural size, viewed edgeways.
Figure 43. Plum stones, of natural size, viewed laterally.
FOREWORD
_Harriet Ritvo_
Charles Darwin wrote _On the Origin of Species_ in a hurry. He had, it
was true, been formulating his ideas and arguments for several
decades—since his round-the-world _Beagle_ voyage of 1831-1836. These
ideas and arguments had been slow to take definitive shape; Darwin had
nurtured and reworked them, amassing evidence for what he projected to
be a weighty magnum opus. Although he had shared his developing
evolutionary speculations with his closest professional colleagues,
Darwin was reluctant to publish them on several grounds. He was aware
that his theory of evolution by natural selection (or descent with
modification) was complex, that it rested on vast but not
incontrovertible evidence, and that the chain of his reasoning was not
uniformly strong. Further, his conclusions challenged not only the
scientific assumptions of many fellow specialists but also the
theological convictions of a much wider circle of fellow citizens.
In 1859, Darwin did not feel quite ready to expose his cherished theory
to the harsh light of public scrutiny. In the introduction to the
_Origin_ he confessed that although his work on evolution by natural
selection was “nearly finished,” he would need “two or three more years
to complete it.” The _ Origin_ was, he suggested, merely a stopgap, a
schematic “abstract” of a much longer and more fully supported treatise
yet to come. He had been moved to preview his labors in this way, he
explained, because his health was “far from strong” and, perhaps more
importantly, because Alfred Russel Wallace, a younger naturalist
working in isolation in southeast Asia, had sent a paper to the Linnean
Society of London in which he “arrived at almost exactly the same
general conclusions that I have on the origin of species.” If Darwin
had not gone public with his theory at this point, he would have risked
losing credit for the work of many years.
As its reception showed immediately and has continued to show, the
_Origin_ benefited from the succinctness imposed by circumstances.
Darwin himself may have appreciated this point; at any rate, he never
produced the massive treatise, although he repeatedly issued revised
editions of the _ Origin._ But he did not abandon his intention to
buttress his initial schematic presentation with additional evidence.
In the course of the next two decades he published several full-length
elaborations of topics summarily discussed in the _Origin: The
Variation of Animals and Plants under Domestication; The Descent of
Man, and Selection in Relation to Sex;_ and _The Expression of the
Emotions in Man and Animals._ In addition to fleshing out the _Origin,_
these subsequent studies bolstered its arguments and responded to
questions raised by critical readers, especially pragmatic questions
about the way that descent with modification actually operated.
In _The Variation of Animals and Plants under Domestication,_ which
appeared first in 1868 and in a revised edition in 1875, Darwin
developed a theme to which he had accorded great rhetorical and
evidentiary significance. He had begun the _ Origin_ with a description
of artificial selection as practiced by farmers, stock breeders, and
pet fanciers, thus using a reassuringly homely example—one recognizable
by the general public as well as by members of the scientific
community—to introduce the most innovative component of his
evolutionary theory. In addition, domesticated animals and plants,
because they were numerous and available for constant observation,
provided a readily available body of evidence.
Reassuring as it was, the analogy between natural and artificial
selection was far from perfect. The point of Darwin’s analogy was to
make the idea of natural selection seem plausible by characterizing it
as a grander version of a well-known process while emphasizing its
efficiency and shaping power. He noted, for example, that some of the
prize birds bred by London pigeon fanciers diverged so strikingly in
size, plumage, beak shape, flying technique, vocalizations. bone
structure, and many other attributes, that if they had been presented
to an ornithologist as wild specimens, they would unquestionably have
been considered to represent distinct species, perhaps even distinct
genera. Darwin argued that if the relatively brief and constrained
selective efforts of human breeders had produced such impressive
results, it was likely that the more protracted and thorough-going
efforts of nature would work still more efficaciously.
But as Darwin acknowledged, there were some fairly obvious reasons why
the two processes might diverge. The superior power of natural
selection—“Man can act only on external and visible characters: nature
. . . can act on . . . the whole machinery of life. Man selects only
for his own good; Nature only for that of the being which she tends”
(_Origin,_ chap. 5)—might constitute a difference of kind rather than
of degree, as might the much greater stretches of time available for
natural selection. Further, although the mechanism of the two processes
appeared superficially similar, their outcomes tended to be rather
different. Natural selection produced a constantly increasing and
diversifying variety of forms; it never reversed or exactly repeated
itself. Anyone familiar with artificial selection would have realized
that, although new breeds were constantly being developed and although
neither improved wheat nor improved cattle showed any tendency to
revert to the condition of their aboriginal wild ancestors, the strains
produced by human selection were neither as prolific nor as durable as
those produced by nature. Indeed, the animals and plants celebrated as
the noblest achievements of the breeder’s art were especially liable to
delicacy and infertility. Highly bred strains, long isolated from
others of their species to preserve their genealogical purity, far from
serving as a springboard for further variation, often had to be
revivified with infusions of less-rarefied blood. Yet any relaxation of
reproductive boundaries threatened subsidence into the common run of
conspecifics.
Darwin firmly connected _Variation_ to the _Origin_ by devoting its
introduction to an overview of his theory of evolution by natural
selection. In particular, the two volumes of _Variation,_ cumbersomely
organized and packed with zoological and botanical detail, addressed
some of the difficulties inherent in the attractive but paradoxical
analogy between natural selection and artificial selection. For
selection of any sort to operate, diversity already had to exist. With
wild populations living under natural conditions, however, diversity
was difficult to discern. It was widely believed that a heightened
propensity to vary (at least in ways obvious to human observers) was
one of the few general characteristics that differentiated domestic
animals as a group from their wild relatives. This point was
conventionally illustrated with reference to coat color and design.
American bison, for example, were, on the whole, brown, and all
Burchell’s zebras shared similar black and white stripes. A single herd
of either _Bos tauras_ or _Equus caballus_ (domestic cattle or horses),
on the other hand, could display colors ranging from white through
yellow, red, and brown to black, as well as a variety of spotted and
blotched patterns.
In order to demonstrate that such populations spontaneously produced
sufficient variation to support artificial selection, Darwin devoted
most of the first volume of _ Variation_ to a species-by-species survey
of domesticated plants and animals. He began with the dog, the breeds
of which differed so greatly in size, shape, disposition, talents, and
every other characteristic that Darwin attributed its exemplary
plasticity to its derivation from several different species of wild
canines. Domestic cats, on the other hand, differed relatively little
from one another, at least, their variation tended to be individual,
rather than consolidated into breeds. Darwin attributed this to the
minimal influence exerted by cat owners over the mating behavior of
their animals, so that, alone among fully domesticated animals, cats
could not be said to have undergone a genuine process of artificial
selection.
Farmyard ungulates, however, had all proved more susceptible to human
manipulation, whether through the gradual enhancement of inherent
tendencies, such as the relatively early maturation that distinguished
shorthorn cattle, or through the preservation of spontaneously arising
monstrosities, such as the short, broad foreheads and protruding lower
jaws of the niata cattle of South America, the bulldogs of the bovine
world. Among animals, fancy pigeons, with their short generations,
devoted breeders, and lack of any pragmatic constraints on their
extravagant deformations, provided Darwin with his most abundant
material. He allotted less space to his survey of domesticated plants,
although, with the exception of trees, they tended to he much shorter
lived and more variable even than pigeons. For example, as Darwin
pointed out, a single long-cultivated species—_Brassica oleracea,_ the
ordinary cabbage—had given rise to strains as distinctive as Brussels
sprouts, cauliflower, broccoli, and kohl-rabi.
Darwin crammed in so much information of this sort that, in order to
confine _Variation_ to two volumes of manageable size, less crucial
evidence was relegated to a smaller typeface. And so compendious was
his survey of domesticates that he felt constrained to deny that it was
intended to he an exhaustive catalog. After all, many such catalogs,
devoted merely to the accumulation of species- or breed-specific data,
existed already; Darwin cited them generously in his footnotes. The
material included in _Variation_ had been chosen to fulfill a more
focused argumentative purpose. Darwin’s theory of descent with
modification required something further than the simple demonstration
that abundant variation existed among domesticated animals and plants.
The accumulated experience of naturalists and breeders offered no clear
explanation of the causes of variation; indeed, no consensus existed on
this issue. Variation under domestication was frequently attributed to
accidental external influences, especially climate and food. But
environmentally induced variation was not of much use to Darwin.
Instead, he sought evidence not only that the tendency to vary was
inherent in domesticated animals and plants but also that specific
variations were inherited.
As a result, Darwin’s wealth of detail in _ Variation_
disproportionately featured strong—as well as puzzling, problematic, or
even questionable—versions of inheritance, in addition to the
unsurprising, if still not completely understood, likelihood that
children would resemble their parents. For example, he devoted an
entire chapter to what he termed “atavism” or “reversion”—that is, the
tendency for offspring to manifest traits apparently derived from their
grandparents, collateral relations, or even remote ancestors, rather
than from their mothers or their fathers. The existence of this
tendency in the lineages of individuals, he argued, incontrovertibly
demonstrated the fact of heritability; and in an extended or
exaggerated version it also demonstrated evolutionary relations between
species. Thus, many breeds of domesticated chickens revealed their
ultimate ancestry by producing occasional sports with the red and
orange plumage of the original _Callus bankiva,_ or jungle fowl.
Like many other naturalists of his time, Darwin was receptive to the
idea of telegony, also known as “the influence of the previous sire.”
He retailed the famous story of Lord Morton’s mare, a chestnut of
seven-eighths Arabian blood, whose first foal had been sired by a
quagga (a now-extinct relative of the zebra) her owner was attempting
to domesticate. It was not surprising that the young hybrid faintly
echoed his father’s stripes, but the fact that her next two foals, both
sired by a black Arabian horse, also seemed to resemble the quagga in
this regard, was more remarkable. Darwin pointed out that atavism
offered one possible explanation of this phenomenon—infant horses and
donkeys often showed evanescent striping, which might indicate the
pattern of their ancient shared progenitor—but he was also drawn to the
notion that the first male to impregnate a female left some permanent,
heritable trace of himself behind. He offered analogous examples from
the vegetable kingdom, where the pollen of related varieties of apples,
corn, or orchids, could not only produce hybrid offspring but
occasionally also physically alter the reproductive tract of the
female. Plants also, and more regularly, demonstrated a kind of
variability that could arise independently of sexual reproduction, such
as “bud variation,” whereby what Darwin called a “monstrosity” might
appear on a single branch or flower and then be transmitted, sexually
or asexually, to future generations.
As he documented the profusion of variation among domesticated animals
and plants, and the tendency of organisms to transmit these variations
down the generations, Darwin did more than demonstrate that there was
ample grist for the mill of natural selection. He also addressed the
most serious weakness in the argument of the _Origin._ Despite the
incompleteness of the fossil record, plenty of evidence suggested that
evolution had taken place; indeed the idea of evolution had been
current in one form or another for a century before 1859. Darwin’s
explanation of the way that natural selection should operate was also
widely persuasive. The competitive metaphors with which he
characterized it, especially the “struggle for life” prominently
featured in the _Origin_’s subtitle, fit well with Victorian
understandings about how things worked in the human arenas of industry,
commerce, and geopolitics. There was, however, a problem that troubled
those inclined to sympathize with Darwin’s reasoning as well as those
inclined to reject it. The efficacy of natural selection, like that of
artificial selection, depended on the inheritance of particular traits.
But before the modern understanding of genetics became available, no
satisfactory mechanism had been adduced to explain this phenomenon. No
consensus yet existed about the way that sexual reproduction worked, so
there was also disagreement about which characteristics were inherited
and which were the result of environment, and what could he contributed
by the male as opposed to the female parent, let alone why offspring
sometimes resembled a grandparent or some more distant relative rather
than their parents. The special difficulty of accounting for the sudden
emergence of monstrosities, or even less dramatically novel traits, led
Darwin, in later editions of the _Origin_ as well as in _Variation,_ to
become increasingly receptive to the notion that characteristics
acquired by one generation might he inherited by the next.
In the penultimate chapter of _Variation,_ Darwin attempted to
strengthen the weak link in his chain of argument by proposing a
mechanism for inheritance. He called his theory “pangenesis,” and he
claimed that it explained not only ordinary inheritance—the influence
of parents on their children—but also reversion, telegony, the
regeneration of amputated limbs in some kinds of animals, the
inheritance of acquired characteristics, and the relationship between
sexual and asexual modes of reproduction and inheritance. The operation
of pangenesis depended on the posited existence of unobservable units
that Darwin called “gemmules,” tiny granules that were thrown off by
individual cells and then circulated through the body. They had,
however, an affinity for each other, which led to their aggregation in
the reproductive organs or in parthenogenetic buds. They could remain
latent for years, until an organism reached a certain stage of
development, or for generations, until they encountered other gemmules
to which they bore some special relationship. In this way a
long-dormant greatgrandparental gemmule might suddenly manifest itself
in a child. Since gemmules could he altered by environmental
influences, they could convert acquired characteristics into the stuff
of heredity. And since they were vulnerable to error, they could
occasionally make mistakes, causing organs, such as limbs or tails or
even heads, to develop in inappropriate numbers or in the wrong places.
It has doubtless been fortunate for Darwin’s reputation that his theory
of pangenesis is not as well remembered as his theory of evolution by
natural selection. As vague in detail as it was ambitious and
comprehensive in scope, it was unpersuasive at the time and has since
been proven completely wrong. But like _Variation_ as a whole, which
similarly illustrated the limitations of its author as well as his
strengths, pangenesis does not therefore lack interest or significance.
Despite recent excellent and well-appreciated studies of his entire
life and extended _oeuvre_ (Janet Browne, _Charles Darwin: Voyaging_
[New York: Knopf, 1995] and Adrian Desmond and James Moore, _Darwin_
[London: Michael Joseph, 1991], Darwin is known primarily as the author
of the _Origin,_ which is unrepresentative in its economy of structure,
argument, and evidence, as well as on account of its historical
notoriety. Its enforced streamlining has helped to preserve the
_Origin_’s accessibility, but its relative paucity of examples was
particularly uncharacteristic of Darwin. _Variation,_ with its
accumulation of evidence about everything from the webbing between
dogs’ toes to the weight of gooseberries, was much more typical; in
addition, it placed Darwin firmly—indeed, irretrievably—within his
time, rather than in an achronological limbo reserved for intellectual
heroes. As a graduate student from the People’s Republic of China told
me several years ago, after having participated in a seminar that read
excerpts from _Variation_ and _The Expression of the Emotions,_ if the
leaders of his government knew that Darwin had written such books, he
would not be officially admired.
In science as in politics the victors tend to write the history books.
As a result, the record of the past is edited, intentionally or
unintentionally, so that it focuses mainly on the precursors of
contemporary orthodoxy. Such a focus may accurately represent the
genealogy of modem ideas, but it almost inevitably misrepresents the
historical experience of their progenitors. Viewed without the benefit
of hindsight, the marketplace of Victorian ideas seemed much more
competitive than it does to us. Even the powerful, persuasive, and
ultimately triumphant theory of evolution by natural selection required
not only defense, but repeated buttressing and revision. _ Variation_
showed Darwin hard at work on this rearguard action, using the
materials he had at hand—for the most part, homely details about the
domesticated animals and plants with which his audience was most
familiar. His information was gleaned from the observations of
fanciers, breeders, and amateur naturalists, as well as from the
treatises of those on the cutting edge of zoology and botany. As
hindsight narrows the historical spotlight, it imposes its own sense of
hierarchy on the preoccupations of the past. But Darwin was interested
in all of these topics, valued all of these sources, and belonged, to a
greater or lesser extent, to all of these communities.
The author of _Variation_ was a Victorian country gentleman, a lover of
dogs and horses, a breeder of pigeons and peas. He was also, and
equally, the author of _On the Origin of Species._
PREFACE TO THE SECOND EDITION
During the seven years which have elapsed since the publication in 1868
of the first edition of this Work, I have continued to attend to the
same subjects, as far as lay in my power; and I have thus accumulated a
large body of additional facts, chiefly through the kindness of many
correspondents. Of these facts I have been able here to use only those
which seemed to me the more important. I have omitted some statements,
and corrected some errors, the discovery of which I owe to my
reviewers. Many additional references have been given. The eleventh
chapter, and that on Pangenesis, are those which have been most
altered, parts having been remodelled; but I will give a list of the
more important alterations for the sake of those who may possess the
first edition of this book.
TABLE OF PRINCIPAL ADDITIONS AND CORRECTIONS IN SECOND
EDITION
First
Edition
Vol. I
Second
Edition
Vol. I
First
Edition
Vol. I
Second
Edition
Vol. I
_Page_ _Chapter_
34 I Dr. Burt Wilder’s observations on the brains
of different breeds of the Dog.
38 I Degeneracy of Dogs imported into
Guinea.
51 II Difference in the number of lumbar
vertebræ in the races or species of the Horse.
102 III Hairy appendages to the throats of
Goats.
162 V Sexual differences in colour in the domestic
Pigeon.
217 VI Movements like those of the Tumbler-pigeon,
caused by injury to the brain.
290 VIII Additional facts with respect to the
Black-shouldered Peacock.
296 VIII Ancient selection of Gold-fish in
China.
314 IX Major Hallett’s ‘Pedigree Wheat.’
326 IX The common radish descended from _Raphanus
raphanistrum._
374 XI Several additional cases of bud-variation
given.
396 XI An abstract of all the cases recently
published of graft-hybrids in the potato, together with a
general summary on graft-hybridisation.
399 XI An erroneous statement with respect to the
pollen of the date-palm affecting the fruit of the
Chamærops omitted.
400 XI New cases of the direct action of pollen on
the mother-plant.
404 XI Additional and remarkable instances of the
actions of the male parent on the future progeny of the
female.
Vol.II
14 XII An erroneous statement corrected, with
respect to the regrowth of supernumerary digits after
amputation.
23 XII Additional facts with respect to the
inherited effects of circumcision.
23 XII Dr. Brown-Séquard on the inherited
effects of operations on the Guinea-pig.
24 XII Other cases of inherited mutilations.
Vol. II
43 XIII An additional case of reversion due to a
cross.
72 XIV Inheritance as limited by sex.
105 XVI Two varieties of maize which cannot be
crossed.
120 XVII Some additional facts on the advantages of
cross-breeding in animals.
123 XVII Discussion on the effects of the close
interbreeding in the case of man.
135
to
141
XVII
Additional cases of plants sterile with
pollen from the same plant.
149 XVIII Mr. Sclater on the infertility of animals
under confinement.
152 XVIII The Aperea a distinct species from the
Guinea-pig.
230 XXI Prof. Jäger on hawks killing
light-coloured pigeons.
273 XXIII Prof. Wisemann on the effects of isolation
in the development of species.
281 XXIII The direct action of the conditions of life
in causing variation.
317 XXIV Mr. Romanes on rudimentary parts.
324
to
328
XXV
Some additional cases of correlated
variability.
339 XXVI On Geoffrey St. Hilaire’s law of _“soi
pour soi.”_
357
to
404
XXVII
The chapter on Pangenesis has been largely
altered and re-modelled; but the essential principles remain
the same.
INTRODUCTION
The object of this work is not to describe all the many races of
animals which have been domesticated by man, and of the plants which
have been cultivated by him; even if I possessed the requisite
knowledge, so gigantic an undertaking would be here superfluous. It is
my intention to give under the head of each species only such facts as
I have been able to collect or observe, showing the amount and nature
of the changes which animals and plants have undergone whilst under
man’s dominion, or which bear on the general principles of variation.
In one case alone, namely in that of the domestic pigeon, I will
describe fully all the chief races, their history, the amount and
nature of their differences, and the probable steps by which they have
been formed. I have selected this case, because, as we shall hereafter
see, the materials are better than in any other; and one case fully
described will in fact illustrate all others. But I shall also describe
domesticated rabbits, fowls, and ducks, with considerable fulness.
The subjects discussed in this volume are so connected that it is not a
little difficult to decide how they can be best arranged. I have
determined in the first part to give, under the heads of the various
animals and plants, a large body of facts, some of which may at first
appear but little related to our subject, and to devote the latter part
to general discussions. Whenever I have found it necessary to give
numerous details, in support of any proposition or conclusion, small
type has been used. The reader will, I think, find this plan a
convenience, for, if he does not doubt the conclusion or care about the
details, he can easily pass them over; yet I may be permitted to say
that some of the discussions thus printed deserve attention, at least
from the professed naturalist.
It may be useful to those who have read nothing about Natural
Selection, if I here give a brief sketch of the whole subject and of
its bearing on the origin of species.[1] This is the more desirable, as
it is impossible in the present work to avoid many allusions to
questions which will be fully discussed in future volumes.
From a remote period, in all parts of the world, man has subjected many
animals and plants to domestication or culture. Man has no power of
altering the absolute conditions of life; he cannot change the climate
of any country; he adds no new element to the soil; but he can remove
an animal or plant from one climate or soil to another, and give it
food on which it did not subsist in its natural state. It is an error
to speak of man “tampering with nature” and causing variability. If a
man drops a piece of iron into sulphuric acid, it cannot be said
strictly that he makes the sulphate of iron, he only allows their
elective affinities to come into play. If organic beings had not
possessed an inherent tendency to vary, man could have done nothing.[2]
He unintentionally exposes his animals and plants to various conditions
of life, and variability supervenes, which he cannot even prevent or
check. Consider the simple case of a plant which has been cultivated
during a long time in its native country, and which consequently has
not been subjected to any change of climate. It has been protected to a
certain extent from the competing roots of plants of other kinds; it
has generally been grown in manured soil; but probably not richer than
that of many an alluvial flat; and lastly, it has been exposed to
changes in its conditions, being grown sometimes in one district and
sometimes in another, in different soils. Under such circumstances,
scarcely a plant can be named, though cultivated in the rudest manner,
which has not given birth to several varieties. It can hardly be
maintained that during the many changes which this earth has undergone,
and during the natural migrations of plants from one land or island to
another, tenanted by different species, that such plants will not often
have been subjected to changes in their conditions analogous to those
which almost inevitably cause cultivated plants to vary. No doubt man
selects varying individuals, sows their seeds, and again selects their
varying offspring. But the initial variation on which man works, and
without which he can do nothing, is caused by slight changes in the
conditions of life, which must often have occurred under nature. Man,
therefore, may be said to have been trying an experiment on a gigantic
scale; and it is an experiment which nature during the long lapse of
time has incessantly tried. Hence it follows that the principles of
domestication are important for us. The main result is that organic
beings thus treated have varied largely, and the variations have been
inherited. This has apparently been one chief cause of the belief long
held by some few naturalists that species in a state of nature undergo
change.
I shall in this volume treat, as fully as my materials permit, the
whole subject of variation under domestication. We may thus hope to
obtain some light, little though it be, on the causes of
variability,—on the laws which govern it, such as the direct action of
climate and food, the effects of use and disuse, and of correlation of
growth,—and on the amount of change to which domesticated organisms are
liable. We shall learn something of the laws of inheritance, of the
effects of crossing different breeds, and on that sterility which often
supervenes when organic beings are removed from their natural
conditions of life, and likewise when they are too closely interbred.
During this investigation we shall see that the principle of Selection
is highly important. Although man does not cause variability and cannot
even prevent it, he can select, preserve, and accumulate the variations
given to him by the hand of nature almost in any way which he chooses;
and thus he can certainly produce a great result. Selection may be
followed either methodically and intentionally, or unconsciously and
unintentionally. Man may select and preserve each successive variation,
with the distinct intention of improving and altering a breed, in
accordance with a preconceived idea; and by thus adding up variations,
often so slight as to be imperceptible by an uneducated eye, he has
effected wonderful changes and improvements. It can, also, be clearly
shown that man, without any intention or thought of improving the
breed, by preserving in each successive generation the individuals
which he prizes most, and by destroying the worthless individuals,
slowly, though surely, induces great changes. As the will of man thus
comes into play, we can understand how it is that domesticated breeds
show adaptation to his wants and pleasures. We can further understand
how it is that domestic races of animals and cultivated races of plants
often exhibit an abnormal character, as compared with natural species;
for they have been modified not for their own benefit, but for that of
man.
In another work I shall discuss, if time and health permit, the
variability of organic beings in a state of nature; namely, the
individual differences presented by animals and plants, and those
slightly greater and generally inherited differences which are ranked
by naturalists as varieties or geographical races. We shall see how
difficult, or rather how impossible it often is, to distinguish between
races and sub-species, as the less well-marked forms have sometimes
been denominated; and again between sub-species and true species. I
shall further attempt to show that it is the common and widely ranging,
or, as they may be called, the dominant species, which most frequently
vary; and that it is the large and flourishing genera which include the
greatest number of varying species. Varieties, as we shall see, may
justly be called incipient species.
But it may be urged, granting that organic beings in a state of nature
present some varieties,—that their organisation is in some slight
degree plastic; granting that many animals and plants have varied
greatly under domestication, and that man by his power of selection has
gone on accumulating such variations until he has made strongly marked
and firmly inherited races; granting all this, how, it may be asked,
have species arisen in a state of nature? The differences between
natural varieties are slight; whereas the differences are considerable
between the species of the same genus, and great between the species of
distinct genera. How do these lesser differences become augmented into
the greater difference? How do varieties, or as I have called them
incipient species, become converted into true and well-defined species?
How has each new species been adapted to the surrounding physical
conditions, and to the other forms of life on which it in any way
depends? We see on every side of us innumerable adaptations and
contrivances, which have justly excited the highest admiration of every
observer. There is, for instance, a fly (Cecidomyia)[3] which deposits
its eggs within the stamens of a Scrophularia, and secretes a poison
which produces a gall, on which the larva feeds; but there is another
insect (Misocampus) which deposits its eggs within the body of the
larva within the gall, and is thus nourished by its living prey; so
that here a hymenopterous insect depends on a dipterous insect, and
this depends on its power of producing a monstrous growth in a
particular organ of a particular plant. So it is, in a more or less
plainly marked manner, in thousands and tens of thousands of cases,
with the lowest as well as with the highest productions of nature.
This problem of the conversion of varieties into species,—that is, the
augmentation of the slight differences characteristic of varieties into
the greater differences characteristic of species and genera, including
the admirable adaptations of each being to its complex organic and
inorganic conditions of life,—has been briefly treated in my ‘Origin of
Species.’ It was there shown that all organic beings, without
exception, tend to increase at so high a ratio, that no district, no
station, not even the whole surface of the land or the whole ocean,
would hold the progeny of a single pair after a certain number of
generations. The inevitable result is an ever-recurrent Struggle for
Existence. It has truly been said that all nature is at war; the
strongest ultimately prevail, the weakest fail; and we well know that
myriads of forms have disappeared from the face of the earth. If then
organic beings in a state of nature vary even in a slight degree, owing
to changes in the surrounding conditions, of which we have abundant
geological evidence, or from any other cause; if, in the long course of
ages, inheritable variations ever arise in any way advantageous to any
being under its excessively complex and changing relations of life; and
it would be a strange fact if beneficial variations did never arise,
seeing how many have arisen which man has taken advantage of for his
own profit or pleasure; if then these contingencies ever occur, and I
do not see how the probability of their occurrence can be doubted, then
the severe and often-recurrent struggle for existence will determine
that those variations, however slight, which are favourable shall be
preserved or selected, and those which are unfavourable shall be
destroyed.
This preservation, during the battle for life, of varieties which
possess any advantage in structure, constitution, or instinct, I have
called Natural Selection; and Mr. Herbert Spencer has well expressed
the same idea by the Survival of the Fittest. The term “natural
selection” is in some respects a bad one, as it seems to imply
conscious choice; but this will be disregarded after a little
familiarity. No one objects to chemists speaking of “elective
affinity;” and certainly an acid has no more choice in combining with a
base, than the conditions of life have in determining whether or not a
new form be selected or preserved. The term is so far a good one as it
brings into connection the production of domestic races by man’s power
of selection, and the natural preservation of varieties and species in
a state of nature. For brevity sake I sometimes speak of natural
selection as an intelligent power;—in the same way as astronomers speak
of the attraction of gravity as ruling the movements of the planets, or
as agriculturists speak of man making domestic races by his power of
selection. In the one case, as in the other, selection does nothing
without variability, and this depends in some manner on the action of
the surrounding circumstances on the organism. I have, also, often
personified the word Nature; for I have found it difficult to avoid
this ambiguity; but I mean by nature only the aggregate action and
product of many natural laws,—and by laws only the ascertained sequence
of events.
It has been shown from many facts that the largest amount of life can
be supported on each area, by great diversification or divergence in
the structure and constitution of its inhabitants. We have, also, seen
that the continued production of new forms through natural selection,
which implies that each new variety has some advantage over others,
inevitably leads to the extermination of the older and less improved
forms. These latter are almost necessarily intermediate in structure,
as well as in descent, between the last-produced forms and their
original parent-species. Now, if we suppose a species to produce two or
more varieties, and these in the course of time to produce other
varieties, the principal of good being derived from diversification of
structure will generally lead to the preservation of the most divergent
varieties; thus the lesser differences characteristic of varieties come
to be augmented into the greater differences characteristic of species,
and, by the extermination of the older intermediate forms, new species
end by being distinctly defined objects. Thus, also, we shall see how
it is that organic beings can be classed by what is called a natural
method in distinct groups—species under genera, and genera under
families.
As all the inhabitants of each country may be said, owing to their high
rate of reproduction, to be striving to increase in numbers; as each
form comes into competition with many other forms in the struggle for
life,—for destroy any one and its place will be seized by others; as
every part of the organisation occasionally varies in some slight
degree, and as natural selection acts exclusively by the preservation
of variations which are advantageous under the excessively complex
conditions to which each being is exposed, no limit exists to the
number, singularity, and perfection of the contrivances and
co-adaptations which may thus be produced. An animal or a plant may
thus slowly become related in its structure and habits in the most
intricate manner to many other animals and plants, and to the physical
conditions of its home. Variations in the organisation will in some
cases be aided by habit, or by the use and disuse of parts, and they
will be governed by the direct action of the surrounding physical
conditions and by correlation of growth.
On the principles here briefly sketched out, there is no innate or
necessary tendency in each being to its own advancement in the scale of
organisation. We are almost compelled to look at the specialisation or
differentiation of parts or organs for different functions as the best
or even sole standard of advancement; for by such division of labour
each function of body and mind is better performed. And as natural
selection acts exclusively through the preservation of profitable
modifications of structure, and as the conditions of life in each area
generally become more and more complex from the increasing number of
different forms which inhabit it and from most of these forms acquiring
a more and more perfect structure, we may confidently believe, that, on
the whole, organisation advances. Nevertheless a very simple form
fitted for very simple conditions of life might remain for indefinite
ages unaltered or unimproved; for what would it profit an infusorial
animalcule, for instance, or an intestinal worm, to become highly
organised? Members of a high group might even become, and this
apparently has often occurred, fitted for simpler conditions of life;
and in this case natural selection would tend to simplify or degrade
the organisation, for complicated mechanism for simple actions would be
useless or even disadvantageous.
The arguments opposed to the theory of Natural Selection, have been
discussed in my ‘Origin of Species,’ as far as the size of that work
permitted, under the following heads: the difficulty in understanding
how very simple organs have been converted by small and graduated steps
into highly perfect and complex organs; the marvellous facts of
Instinct; the whole question of Hybridity; and, lastly, the absence in
our known geological formations of innumerable links connecting all
allied species. Although some of these difficulties are of great
weight, we shall see that many of them are explicable on the theory of
natural selection, and are otherwise inexplicable.
In scientific investigations it is permitted to invent any hypothesis,
and if it explains various large and independent classes of facts it
rises to the rank of a well-grounded theory. The undulations of the
ether and even its existence are hypothetical, yet every one now admits
the undulatory theory of light. The principle of natural selection may
be looked at as a mere hypothesis, but rendered in some degree probable
by what we positively know of the variability of organic beings in a
state of nature,—by what we positively know of the struggle for
existence, and the consequent almost inevitable preservation of
favourable variations,—and from the analogical formation of domestic
races. Now this hypothesis may be tested,—and this seems to me the only
fair and legitimate manner of considering the whole question,—by trying
whether it explains several large and independent classes of facts;
such as the geological succession of organic beings, their distribution
in past and present times, and their mutual affinities and homologies.
If the principle of natural selection does explain these and other
large bodies of facts, it ought to be received. On the ordinary view of
each species having been independently created, we gain no scientific
explanation of any one of these facts. We can only say that it has so
pleased the Creator to command that the past and present inhabitants of
the world should appear in a certain order and in certain areas; that
He has impressed on them the most extraordinary resemblances, and has
classed them in groups subordinate to groups. But by such statements we
gain no new knowledge; we do not connect together facts and laws; we
explain nothing.
It was the consideration of such large groups of facts as these which
first led me to take up the present subject. When I visited during the
voyage of H.M.S. _Beagle,_ the Galapagos Archipelago, situated in the
Pacific Ocean about 500 miles from South America, I found myself
surrounded by peculiar species of birds, reptiles, and plants, existing
nowhere else in the world. Yet they nearly all bore an American stamp.
In the song of the mocking-thrush, in the harsh cry of the
carrion-hawk, in the great candlestick-like opuntias, I clearly
perceived the neighbourhood of America, though the islands were
separated by so many miles of ocean from the mainland, and differed
much in their geological constitution and climate. Still more
surprising was the fact that most of the inhabitants of each separate
island in this small archipelago were specifically different, though
most closely related to each other. The archipelago, with its
innumerable craters and bare streams of lava, appeared to be of recent
origin; and thus I fancied myself brought near to the very act of
creation. I often asked myself how these many peculiar animals and
plants had been produced: the simplest answer seemed to be that the
inhabitants of the several islands had descended from each other,
undergoing modification in the course of their descent; and that all
the inhabitants of the archipelago were descended from those of the
nearest land, namely America, whence colonists would naturally have
been derived. But it long remained to me an inexplicable problem how
the necessary degree of modification could have been effected, and it
would have thus remained for ever, had I not studied domestic
productions, and thus acquired a just idea of the power of Selection.
As soon as I had fully realised this idea, I saw, on reading Malthus on
Population, that Natural Selection was the inevitable result of the
rapid increase of all organic beings; for I was prepared to appreciate
the struggle for existence by having long studied the habits of
animals.
Before visiting the Galapagos I had collected many animals whilst
travelling from north to south on both sides of America, and
everywhere, under conditions of life as different as it is possible to
conceive, American forms were met with—species replacing species of the
same peculiar genera. Thus it was when the Cordilleras were ascended,
or the thick tropical forests penetrated, or the fresh waters of
America searched. Subsequently I visited other countries, which in all
their conditions of life were incomparably more like parts of South
America, than the different parts of that continent are to each other;
yet in these countries, as in Australia or Southern Africa, the
traveller cannot fail to be struck with the entire difference of their
productions. Again the reflection was forced on me that community of
descent from the early inhabitants of South America would alone explain
the wide prevalence of American types throughout that immense area.
To exhume with one’s own hands the bones of extinct and gigantic
quadrupeds brings the whole question of the succession of species
vividly before one’s mind; and I found in South America great pieces of
tesselated armour exactly like, but on a magnificent scale, that
covering the pigmy armadillo; I had found great teeth like those of the
living sloth, and bones like those of the cavy. An analogous succession
of allied forms had been previously observed in Australia. Here then we
see the prevalence, as if by descent, in time as in space, of the same
types in the same areas; and in neither the case does the similarity of
the conditions by any means seem sufficient to account for the
similarity of the forms of life. It is notorious that the fossil
remains of closely consecutive formations are closely allied in
structure, and we can at once understand the fact if they are closely
allied by descent. The succession of the many distinct species of the
same genus throughout the long series of geological formations seems to
have been unbroken or continuous. New species come in gradually one by
one. Ancient and extinct forms of life are often intermediate in
character, like the words of a dead language with respect to its
several offshoots or living tongues. All these facts seemed to me to
point to descent with modification as the means of production of new
species.
The innumerable past and present inhabitants of the world are connected
together by the most singular and complex affinities, and can be
classed in groups under groups, in the same manner as varieties can be
classed under species and sub-varieties under varieties, but with much
higher grades of difference. These complex affinities and the rules for
classification, receive a rational explanation on the theory of
descent, combined with the principle of natural selection, which
entails divergence of character and the extinction of intermediate
forms. How inexplicable is the similar pattern of the hand of a man,
the foot of a dog, the wing of a bat, the flipper of a seal, on the
doctrine of independent acts of creation! how simply explained on the
principle of the natural selection of successive slight variations in
the diverging descendants from a single progenitor! So it is with
certain parts or organs in the same individual animal or plant, for
instance, the jaws and legs of a crab, or the petals, stamens, and
pistils of a flower. During the many changes to which in the course of
time organic beings have been subjected, certain organs or parts have
occasionally become at first of little use and ultimately superfluous;
and the retention of such parts in a rudimentary and useless condition
is intelligible on the theory of descent. It can be shown that
modifications of structure are generally inherited by the offspring at
the same age at which each successive variation appeared in the
parents; it can further be shown that variations do not commonly
supervene at a very early period of embryonic growth, and on these two
principles we can understand that most wonderful fact in the whole
circuit of natural history, namely, the close similarity of the embryos
within the same great class—for instance, those of mammals, birds,
reptiles, and fish.
It is the consideration and explanation of such facts as these which
has convinced me that the theory of descent with modification by means
of natural selection is in the main true. These facts have as yet
received no explanation on the theory of independent Creation; they
cannot be grouped together under one point of view, but each has to be
considered as an ultimate fact. As the first origin of life on this
earth, as well as the continued life of each individual, is at present
quite beyond the scope of science, I do not wish to lay much stress on
the greater simplicity of the view of a few forms or of only one form
having been originally created, instead of innumerable miraculous
creations having been necessary at innumerable periods; though this
more simple view accords well with Maupertuis’s philosophical axiom of
“least action.”
In considering how far the theory of natural selection may be extended,
—that is, in determining from how many progenitors the inhabitants of
the world have descended,—we may conclude that at least all the members
of the same class have descended from a single ancestor. A number of
organic beings are included in the same class, because they present,
independently of their habits of life, the same fundamental type of
structure, and because they graduate into each other. Moreover, members
of the same class can in most cases be shown to be closely alike at an
early embryonic age. These facts can be explained on the belief of
their descent from a common form; therefore it may be safely admitted
that all the members of the same class are descended from one
progenitor. But as the members of quite distinct classes have something
in common in structure and much in common in constitution, analogy
would lead us one step further, and to infer as probable that all
living creatures are descended from a single prototype.
I hope that the reader will pause before coming to any final and
hostile conclusion on the theory of natural selection. The reader may
consult my ‘Origin of Species’ for a general sketch of the whole
subject; but in that work he has to take many statements on trust. In
considering the theory of natural selection, he will assuredly meet
with weighty difficulties, but these difficulties relate chiefly to
subjects—such as the degree of perfection of the geological record, the
means of distribution, the possibility of transitions in organs,
etc.—on which we are confessedly ignorant; nor do we know how ignorant
we are. If we are much more ignorant than is generally supposed, most
of these difficulties wholly disappear. Let the reader reflect on the
difficulty of looking at whole classes of facts from a new point of
view. Let him observe how slowly, but surely, the noble views of Lyell
on the gradual changes now in progress on the earth’s surface have been
accepted as sufficient to account for all that we see in its past
history. The present action of natural selection may seem more or less
probable; but I believe in the truth of the theory, because it
collects, under one point of view, and gives a rational explanation of,
many apparently independent classes of facts.[4]
REFERENCES
[1] To any one who has attentively read my ‘Origin of Species’ this
Introduction will be superfluous. As I stated in that work that I
should soon publish the facts on which the conclusions given in it
were founded, I here beg permission to remark that the great delay in
publishing this first work has been caused by continued ill-health.
[2] M. Pouchet has recently (‘Plurality of Races,’ Eng. Translat.,
1864, p. 83, etc.) insisted that variation under domestication throws
no light on the natural modification of species. I cannot perceive the
force of his arguments, or, to speak more accurately, of his
assertions to this effect.
[3] Léon Dufour in ‘Annales des Science. Nat.’ (3rd series, Zoolog.),
tom. v. p. 6.
[4] In treating the several subjects included in the present and my
other works I have continually been led to ask for information from
many zoologists, botanists, geologists, breeders of animals, and
horticulturists, and I have invariably received from them the most
generous assistance. Without such aid I could have effected little. I
have repeatedly applied for information and specimens to foreigners,
and to British merchants and officers of the Government residing in
distant lands, and, with the rarest exceptions, I have received
prompt, open-handed, and valuable assistance. I cannot express too
strongly my obligations to the many persons who have assisted me, and
who, I am convinced, would be equally willing to assist others in any
scientific investigation.
CHAPTER I. DOMESTIC DOGS AND CATS.
ANCIENT VARIETIES OF THE DOG—RESEMBLANCE OF DOMESTIC DOGS IN VARIOUS
COUNTRIES TO NATIVE CANINE SPECIES—ANIMALS NOT ACQUAINTED WITH MAN AT
FIRST FEARLESS—DOGS RESEMBLING WOLVES AND JACKALS—HABIT OF BARKING
ACQUIRED AND LOST—FERAL DOGS—TAN-COLOURED EYE-SPOTS—PERIOD OF
GESTATION—OFFENSIVE ODOUR—FERTILITY OF THE RACES WHEN
CROSSED—DIFFERENCES IN THE SEVERAL RACES IN PART DUE TO DESCENT FROM
DISTINCT SPECIES—DIFFERENCES IN THE SKULL AND TEETH—DIFFERENCES IN THE
BODY, IN CONSTITUTION—FEW IMPORTANT DIFFERENCES HAVE BEEN FIXED BY
SELECTION—DIRECT ACTION OF CLIMATE—WATER-DOGS WITH PALMATED
FEET—HISTORY OF THE CHANGES WHICH CERTAIN ENGLISH RACES OF THE DOG HAVE
GRADUALLY UNDERGONE THROUGH SELECTION—EXTINCTION OF THE LESS IMPROVED
SUB-BREEDS.
CATS, CROSSED WITH SEVERAL SPECIES—DIFFERENT BREEDS FOUND ONLY IN
SEPARATED COUNTRIES—DIRECT EFFECTS OF THE CONDITIONS OF LIFE—FERAL
CATS—INDIVIDUAL VARIABILITY.
The first and chief point of interest in this chapter is, whether
the numerous domesticated varieties of the dog have descended from
a single wild species, or from several. Some authors believe that
all have descended from the wolf, or from the jackal, or from an
unknown and extinct species. Others again believe, and this of late
has been the favourite tenet, that they have descended from several
species, extinct and recent, more or less commingled together. We
shall probably never be able to ascertain their origin with
certainty. Palæontology[1] does not throw much light on the
question, owing, on the one hand, to the close similarity of the
skulls of extinct as well as living wolves and jackals, and owing,
on the other hand, to the great dissimilarity of the skulls of the
several breeds of the domestic dogs. It seems, however, that
remains have been found in the later tertiary deposits more like
those of a large dog than of a wolf, which favours the belief of De
Blainville that our dogs are the descendants of a single extinct
species. On the other hand, some authors go so far as to assert
that every chief domestic breed must have had its wild prototype.
This latter view is extremely improbable: it allows nothing for
variation; it passes over the almost monstrous character of some of
the breeds; and it almost necessarily assumes that a large number
of species have become extinct since man domesticated the dog;
whereas we plainly see that wild members of the dog-family are
extirpated by human agency with much difficulty; even so recently
as 1710 the wolf existed in so small an island as Ireland.
The reasons which have led various authors to infer that our dogs
have descended from more than one wild species are as follows.[2]
Firstly, the great difference between the several breeds; but this
will appear of comparatively little weight, after we shall have
seen how great are the differences between the several races of
various domesticated animals which certainly have descended from a
single parent-form. Secondly, the more important fact, that, at the
most anciently known historical periods, several breeds of the dog
existed, very unlike each other, and closely resembling or
identical with breeds still alive.
We will briefly run back through the historical records. The
materials are remarkably deficient between the fourteenth century
and the Roman classical period.[3] At this latter period various
breeds, namely hounds, house-dogs, lapdogs, etc, existed; but, as
Dr. Walther has remarked, it is impossible to recognise the greater
number with any certainty. Youatt, however, gives a drawing of a
beautiful sculpture of two greyhound puppies from the Villa of
Antoninus. On an Assyrian monument, about 640 B.C., an enormous
mastiff[4] is figured; and according to Sir H. Rawlinson (as I was
informed at the British Museum), similar dogs are still imported
into this same country. I have looked through the magnificent works
of Lepsius and Rosellini, and on the Egyptian monuments from the
fourth to the twelfth dynasties (i.e. from about 3400 B.C. to 2100
B.C.) several varieties of the dog are represented; most of them
are allied to greyhounds; at the later of these periods a dog
resembling a hound is figured, with drooping ears, but with a
longer back and more pointed head than in our hounds. There is,
also, a turnspit, with short and crooked legs, closely resembling
the existing variety; but this kind of monstrosity is so common
with various animals, as with the ancon sheep, and even, according
to Rengger, with jaguars in Paraguay, that it would be rash to look
at the monumental animal as the parent of all our turnspits:
Colonel Sykes[5] also has described an Indian pariah dog as
presenting the same monstrous character. The most ancient dog
represented on the Egyptian monuments is one of the most singular;
it resembles a greyhound, but has long pointed ears and a short
curled tail: a closely allied variety still exists in Northern
Africa; for Mr. E. Vernon Harcourt[6] states that the Arab
boar-hound is “an eccentric hieroglyphic animal, such as Cheops
once hunted with, somewhat resembling the rough Scotch deer-hound;
their tails are curled tight round on their backs, and their ears
stick out at right angles.” With this most ancient variety a
pariah-like dog coexisted.
We thus see that, at a period between four and five thousand years
ago, various breeds, viz. pariah dogs, greyhounds, common hounds,
mastiffs, house-dogs, lapdogs, and turnspits, existed, more or less
closely resembling our present breeds. But there is not sufficient
evidence that any of these ancient dogs belonged to the same
identical sub-varieties with our present dogs.[7] As long as man
was believed to have existed on this earth only about 6000 years,
this fact of the great diversity of the breeds at so early a period
was an argument of much weight that they had proceeded from several
wild sources, for there would not have been sufficient time for
their divergence and modification. But now that we know, from the
discovery of flint tools embedded with the remains of extinct
animals in districts which have since undergone great geographical
changes, that man has existed for an incomparably longer period,
and bearing in mind that the most barbarous nations possess
domestic dogs, the argument from insufficient time falls away
greatly in value.
Long before the period of any historical record the dog was
domesticated in Europe. In the Danish Middens of the Neolithic or
Newer Stone period, bones of a canine animal are embedded, and
Steenstrup ingeniously argues that these belonged to a domestic
dog; for a very large proportion of the bones of birds preserved in
the refuse consists of long bones, which it was found on trial dogs
cannot devour.[8] This ancient dog was succeeded in Denmark during
the Bronze period by a larger kind, presenting certain differences,
and this again during the Iron period, by a still larger kind. In
Switzerland, we hear from Prof. Rütimeyer,[9] that during the
Neolithic period a domesticated dog of middle size existed, which
in its skull was about equally remote from the wolf and jackal, and
partook of the characters of our hounds and setters or spaniels
(Jagdhund und Wachtelhund). Rütimeyer insists strongly on the
constancy of form during a very long period of time of this the
most ancient known dog. During the Bronze period a larger dog
appeared, and this closely resembled in its jaw a dog of the same
age in Denmark. Remains of two notably distinct varieties of the
dog were found by Schmerling in a cave;[10] but their age cannot be
positively determined.
The existence of a single race, remarkably constant in form during
the whole Neolithic period, is an interesting fact in contrast with
what we see of the changes which the races underwent during the
period of the successive Egyptian monuments, and in contrast with
our existing dogs. The character of this animal during the
Neolithic period, as given by Rütimeyer, supports De Blainville’s
view that our varieties have descended from an unknown and extinct
form. But we should not forget that we know nothing with respect to
the antiquity of man in the warmer parts of the world. The
succession of the different kinds of dogs in Switzerland and
Denmark is thought to be due to the immigration of conquering
tribes bringing with them their dogs; and this view accords with
the belief that different wild canine animals were domesticated in
different regions. Independently of the immigration of new races of
man, we know from the wide-spread presence of bronze, composed of
an alloy of tin, how much commerce there must have been throughout
Europe at an extremely remote period, and dogs would then probably
have been bartered. At the present time, amongst the savages of the
interior of Guiana, the Taruma Indians are considered the best
trainers of dogs, and possess a large breed which they barter at a
high price with other tribes.[11]
The main argument in favour of the several breeds of the dog being
the descendants of distinct wild stocks, is their resemblance in
various countries to distinct species still existing there. It
must, however, be admitted that the comparison between the wild and
domesticated animal has been made but in few cases with sufficient
exactness. Before entering on details, it will be well to show that
there is no a priori difficulty in the belief that several canine
species have been domesticated. Members of the dog family inhabit
nearly the whole world; and several species agree pretty closely in
habits and structure with our several domesticated dogs. Mr. Galton
has shown[12] how fond savages are of keeping and taming animals of
all kinds. Social animals are the most easily subjugated by man,
and several species of Canidæ hunt in packs. It deserves notice, as
bearing on other animals as well as on the dog, that at an
extremely ancient period, when man first entered any country, the
animals living there would have felt no instinctive or inherited
fear of him, and would consequently have been tamed far more easily
than at present. For instance, when the Falkland Islands were first
visited by man, the large wolf-like dog (_Canis antarcticus_)
fearlessly came to meet Byron’s sailors, who, mistaking this
ignorant curiosity for ferocity, ran into the water to avoid them:
even recently a man, by holding a piece of meat in one hand and a
knife in the other, could sometimes stick them at night. On a
island in the Sea of Aral, when first discovered by Butakoff, the
saigak antelopes, which are “generally very timid and watchful, did
not fly from us, but on the contrary looked at us with a sort of
curiosity.” So, again, on the shores of the Mauritius, the manatee
was not at first in the least afraid of man, and thus it has been
in several quarters of the world with seals and the morse. I have
elsewhere shown[13] how slowly the native birds of several islands
have acquired and inherited a salutary dread of man: at the
Galapagos Archipelago I pushed with the muzzle of my gun hawks from
a branch, and held out a pitcher of water for other birds to alight
on and drink. Quadrupeds and birds which have seldom been disturbed
by man, dread him no more than do our English birds, the cows, or
horses grazing in the fields.
It is a more important consideration that several canine species evince
(as will be shown in a future chapter) no strong repugnance or
inability to breed under confinement; and the incapacity to breed under
confinement is one of the commonest bars to domestication. Lastly,
savages set the highest value, as we shall see in the chapter on
Selection, on dogs: even half-tamed animals are highly useful to them:
the Indians of North America cross their half-wild dogs with wolves,
and thus render them even wilder than before, but bolder: the savages
of Guiana catch and partially tame and use the whelps of two wild
species of _Canis,_ as do the savages of Australia those of the wild
Dingo. Mr. Philip King informs me that he once trained a wild Dingo
puppy to drive cattle, and found it very useful. From these several
considerations we see that there is no difficulty in believing that man
might have domesticated various canine species in different countries.
It would indeed have been a strange fact if one species alone had been
domesticated throughout the world.
We will now enter into details. The accurate and sagacious
Richardson says, “The resemblance between the Northern American
wolves (_Canis lupus,_ var. _occidentalis_) and the domestic dogs
of the Indians is so great that the size and strength of the wolf
seems to be the only difference. I have more than once mistaken a
band of wolves for the dogs of a party of Indians; and the howl of
the animals of both species is prolonged so exactly in the same key
that even the practised ear of the Indian fails at times to
discriminate them.” He adds that the more northern Esquimaux dogs
are not only extremely like the grey wolves of the Arctic circle in
form and colour, but also nearly equal them in size. Dr. Kane has
often seen in his teams of sledge-dogs the oblique eye (a character
on which some naturalists lay great stress), the drooping tail, and
scared look of the wolf. In disposition the Esquimaux dogs differ
little from wolves, and, according to Dr. Hayes, they are capable
of no attachment to man, and are so savage that when hungry they
will attack even their masters. According to Kane they readily
become feral. Their affinity is so close with wolves that they
frequently cross with them, and the Indians take the whelps of
wolves “to improve the breed of their dogs.” The half-bred wolves
sometimes (Lamare-Picquot) cannot be tamed, “though this case is
rare;” but they do not become thoroughly well broken in till the
second or third generation. These facts show that there can be but
little, if any, sterility between the Esquimaux dog and the wolf,
for otherwise they would not be used to improve the breed. As Dr.
Hayes says of these dogs, “reclaimed wolves they doubtless
are.”[14]
North America is inhabited by a second kind of wolf, the
prairie-wolf (_Canis latrans_), which is now looked at by all
naturalists as specifically distinct from the common wolf; and is,
according to Mr. J.K. Lord, in some respects intermediate in habits
between a wolf and a fox. Sir J. Richardson, after describing the
Hare Indian dog, which differs in many respects from the Esquimaux
dog, says, “It bears the same relation to the prairie-wolf that the
Esquimaux dog does to the great grey wolf.” He could, in fact,
detect no marked difference between them; and Messrs. Nott and
Gliddon give additional details showing their close resemblance.
The dogs derived from the above two aboriginal sources cross
together and with the wild wolves, at least with the _C.
occidentalis,_ and with European dogs. In Florida, according to
Bartram, the black wolf-dog of the Indians differs in nothing from
the wolves of that country except in barking.[15]
Turning to the southern parts of the new world, Columbus found two
kinds of dogs in the West Indies; and Fernandez[16] describes three
in Mexico: some of these native dogs were dumb—that is, did not
bark. In Guiana it has been known since the time of Buffon that the
natives cross their dogs with an aboriginal species, apparently the
_Canis cancrivorus._ Sir R. Schomburgk, who has so carefully
explored these regions, writes to me, “I have been repeatedly told
by the Arawaak Indians, who reside near the coast, that they cross
their dogs with a wild species to improve the breed, and individual
dogs have been shown to me which certainly resembled the _C.
cancrivorus_ much more than the common breed. It is but seldom that
the Indians keep the _C. cancrivorus_ for domestic purposes, nor is
the Ai, another species of wild dog, and which I consider to be
identical with the _Dusicyon silvestris_ of H. Smith, now much used
by the Arecunas for the purpose of hunting. The dogs of the Taruma
Indians are quite distinct, and resemble Buffon’s St. Domingo
greyhound.” It thus appears that the natives of Guiana have
partially domesticated two aboriginal species, and still cross
their dogs with them; these two species belong to a quite different
type from the North American and European wolves. A careful
observer, Rengger,[17] gives reasons for believing that a hairless
dog was domesticated when America was first visited by Europeans:
some of these dogs in Paraguay are still dumb, and Tschudi[18]
states that they suffer from cold in the Cordillera. This naked dog
is, however quite distinct from that found preserved in the ancient
Peruvian burial-places, and described by Tschudi, under the name of
_Canis ingæ,_ as withstanding cold well and as barking. It is not
known whether these two distinct kinds of dog are the descendants
of native species, and it might be argued that when man first
migrated into America he brought with him from the Asiatic
continent dogs which had not learned to bark; but this view does
not seem probable, as the natives along the line of their march
from the north reclaimed, as we have seen, at least two N. American
species of Canidæ.
Turning to the Old World, some European dogs closely resemble the
wolf; thus the shepherd dog of the plains of Hungary is white or
reddish-brown, has a sharp nose, short, erect ears, shaggy coat,
and bushy tail, and so much resembles a wolf that Mr. p.t, who
gives this description, says he has known a Hungarian mistake a
wolf for one of his own dogs. Jeitteles, also, remarks on the close
similarity of the Hungarian dog and wolf. Shepherd dogs in Italy
must anciently have closely resembled wolves, for Columella (vii.
12) advises that white dogs be kept, adding, “pastor album probat,
ne pro lupo canem feriat.” Several accounts have been given of dogs
and wolves crossing naturally; and Pliny asserts that the Gauls
tied their female dogs in the woods that they might cross with
wolves.[19] The European wolf differs slightly from that of North
America, and has been ranked by many naturalists as a distinct
species. The common wolf of India is also by some esteemed as a
third species, and here again we find a marked resemblance between
the pariah dogs of certain districts of India and the Indian
wolf.[20]
With respect to Jackals, Isidore Geoffroy Saint-Hilaire[21] says
that not one constant difference can be pointed out between their
structure and that of the smaller races of dogs. They agree closely
in habits: jackals, when tamed and called by their master, wag
their tails, lick his hands, crouch, and throw themselves on their
backs; they smell at the tails of other dogs, and void their urine
sideways; they roll on carrion or on animals which they have
killed; and, lastly, when in high spirits, they run round in
circles or in a figure of eight, with their tails between their
legs.[22] A number of excellent naturalists, from the time of
Güldenstädt to that of Ehrenberg, Hemprich, and Cretzschmar, have
expressed themselves in the strongest terms with respect to the
resemblance of the half-domestic dogs of Asia and Egypt to jackals.
M. Nordmann, for instance, says, “Les chiens d’Awhasie ressemblent
étonnamment à des chacals.” Ehrenberg[23] asserts that the domestic
dogs of Lower Egypt, and certain mummied dogs, have for their wild
type a species of wolf (_C. lupaster_) of the country; whereas the
domestic dogs of Nubia and certain other mummied dogs have the
closest relation to a wild species of the same country, viz. _C.
sabbar,_ which is only a form of the common jackal. Pallas asserts
that jackals and dogs sometimes naturally cross in the East; and a
case is on record in Algeria.[24] The greater number of naturalists
divide the jackals of Asia and Africa into several species, but
some few rank them all as one.
I may add that the domestic dogs on the coast of Guinea are
fox-like animals, and are dumb.[25] On the east coast of Africa,
between latitude 4° and 6° south, and about ten days’ journey in
the interior, a semi-domestic dog, as the Rev. S. Erhardt informs
me, is kept, which the natives assert is derived from a similar
wild animal. Lichtenstein[26] says that the dogs of the Bosjemans
present a striking resemblance even in colour (excepting the black
stripe down the back) with the _C. mesomelas_ of South Africa. Mr.
E. Layard informs me that he has seen a Caffre dog which closely
resembled an Esquimaux dog. In Australia the Dingo is both
domesticated and wild; though this animal may have been introduced
aboriginally by man, yet it must be considered as almost an endemic
form, for its remains have been found in a similar state of
preservation and associated with extinct mammals, so that its
introduction must have been ancient.[27]
From this resemblance of the half-domesticated dogs in several
countries to the wild species still living there,—from the facility
with which they can often be crossed together,—from even half-tamed
animals being so much valued by savages,—and from the other
circumstances previously remarked on which favour their
domestication, it is highly probable that the domestic dogs of the
world are descended from two well-defined species of wolf (viz. _C.
lupus_ and _C. latrans),_ and from two or three other doubtful
species (namely, the European, Indian, and North African wolves);
from at least one or two South American canine species; from
several races or species of jackal; and perhaps from one or more
extinct species. Although it is possible or even probable that
domesticated dogs, introduced into any country and bred there for
many generations, might acquire some of the characters proper to
the aboriginal Canidæ of the country, we can hardly thus account
for introduced dogs having given rise to two breeds in the same
country, resembling two of its aboriginal species, as in the
above-given cases of Guiana and of North America.[28]
It cannot be objected to the view of several canine species having
been anciently domesticated, that these animals are tamed with
difficulty: facts have been already given on this head, but I may
add that the young of the _Canis primævus_ of India were tamed by
Mr. Hodgson,[29] and became as sensible of caresses, and manifested
as much intelligence, as any sporting dog of the same age. There is
not much difference, as we have already shown and shall further
see, in habits between the domestic dogs of the North American
Indians and the wolves of that country, or between the Eastern
pariah dogs and jackals, or between the dogs which have run wild in
various countries and the several natural species of the family.
The habit of barking, however, which is almost universal with
domesticated dogs, forms an exception, as it does not characterise
a single natural species of the family, though I am assured that
the _Canis latrans_ of North America utters a noise which closely
approaches a bark. But this habit is soon lost by dogs when they
become feral and is soon reacquired when they are again
domesticated. The case of the wild dogs on the island of Juan
Fernandez having become dumb has often been quoted, and there is
reason to believe[30] that the dumbness ensued in the course of
thirty-three years; on the other hand, dogs taken from this island
by Ulloa slowly reacquired the habit of barking. The
Mackenzie-river dogs, of the _Canis latrans_ type, when brought to
England, never learned to bark properly; but one born in the
Zoological Gardens[31] “made his voice sound as loudly as any other
dog of the same age and size.” According to Professor Nillson,[32]
a wolf-whelp reared by a bitch barks. I. Geoffroy Saint-Hilaire
exhibited a jackal which barked with the same tone as any common
dog.[33] An interesting account has been given by Mr. G. Clarke[34]
of some dogs run wild on Juan de Nova, in the Indian Ocean; “they
had entirely lost the faculty of barking; they had no inclination
for the company of other dogs, nor did they acquire their voice”
during a captivity of several months. On the island they
“congregate in vast packs, and catch sea-birds with as much address
as foxes could display.” The feral dogs of La Plata have not become
dumb; they are of large size, hunt singly or in packs, and burrow
holes for their young.[35] In these habits the feral dogs of La
Plata resemble wolves and jackals; both of which hunt either singly
or in packs, and burrow holes.[36] These feral dogs have not become
uniform in colour on Juan Fernandez, Juan de Nova, or La Plata.[37]
In Cuba the feral dogs are described by Poeppig as nearly all
mouse-coloured, with short ears and light-blue eyes. In St.
Domingo, Col. Ham. Smith says[38] that the feral dogs are very
large, like greyhounds, of a uniform pale blue-ash, with small
ears, and large light-brown eyes. Even the wild Dingo, though so
anciently naturalised in Australia, “varies considerably in
colour,” as I am informed by Mr. P.P. King: a half-bred Dingo
reared in England[39] showed signs of wishing to burrow.
From the several foregoing facts we see that reversion in the feral
state gives no indication of the colour or size of the aboriginal
parent-species. One fact, however, with respect to the colouring of
domestic dogs, I at one time hoped might have thrown some light on
their origin; and it is worth giving, as showing how colouring
follows laws, even in so anciently and thoroughly domesticated an
animal as the dog. Black dogs with tan-coloured feet, whatever
breed they may belong to, almost invariably have a tan-coloured
spot on the upper and inner corners of each eye, and their lips are
generally thus coloured. I have seen only two exceptions to this
rule, namely, in a spaniel and terrier. Dogs of a light-brown
colour often have a lighter, yellowish-brown spot over the eyes;
sometimes the spot is white, and in a mongrel terrier the spot was
black. Mr. Waring kindly examined for me a stud of fifteen
greyhounds in Suffolk: eleven of them were black, or black and
white, or brindled, and these had no eye-spots; but three were red
and one slaty-blue, and these four had dark-coloured spots over
their eyes. Although the spots thus sometimes differ in colour,
they strongly tend to be tan-coloured; this is proved by my having
seen four spaniels, a setter, two Yorkshire shepherd dogs, a large
mongrel, and some fox-hounds, coloured black and white, with not a
trace of tan-colour, excepting the spots over the eyes, and
sometimes a little on the feet. These latter cases, and many
others, show plainly that the colour of the feet and the eye-spots
are in some way correlated. I have noticed, in various breeds,
every gradation, from the whole face being tan-coloured, to a
complete ring round the eyes, to a minute spot over the inner and
upper corners. The spots occur in various sub-breeds of terriers
and spaniels; in setters; in hounds of various kinds, including the
turnspit-like German badger-hound; in shepherd dogs; in a mongrel,
of which neither parent had the spots; in one pure bulldog, though
the spots were in this case almost white; and in greyhounds,—but
true black-and-tan greyhounds are excessively rare; nevertheless I
have been assured by Mr. Warwick, that one ran at the Caledonian
Champion meeting of April 1860, and was “marked precisely like a
black-and-tan terrier.” This dog, or another exactly the same
colour, ran at the Scottish National Club on the 21st of March,
1865; and I hear from Mr. C. M. Browne, that “there was no reason
either on the sire or dam side for the appearance of this unusual
colour.” Mr. Swinhoe at my request looked at the dogs in China, at
Amoy, and he soon noticed a brown dog with yellow spots over the
eyes. Colonel H. Smith[40] figures the magnificent black mastiff of
Thibet with a tan-coloured stripe over the eyes, feet, and chaps;
and what is more singular, he figures the Alco, or native domestic
dog of Mexico, as black and white, with narrow tan-coloured rings
round the eyes; at the Exhibition of dogs in London, May 1863, a
so-called forest dog from North-West Mexico was shown, which had
pale tan-coloured spots over the eyes. The occurrence of these
tan-coloured spots in dogs of such extremely different breeds,
living in various parts of the world, makes the fact highly
remarkable.
We shall hereafter see, especially in the chapter on Pigeons, that
coloured marks are strongly inherited, and that they often aid us
in discovering the primitive forms of our domestic races. Hence, if
any wild canine species had distinctly exhibited the tan-coloured
spots over the eyes, it might have been argued that this was the
parent-form of nearly all our domestic races. But after looking at
many coloured plates, and through the whole collection of skins in
the British Museum, I can find no species thus marked. It is no
doubt possible that some extinct species was thus coloured. On the
other hand, in looking at the various species, there seems to be a
tolerably plain correlation between tan-coloured legs and face; and
less frequently between black legs and a black face; and this
general rule of colouring explains to a certain extent the
above-given cases of correlation between the eye-spots and the
colour of the feet. Moreover, some jackals and foxes have a trace
of a white ring round their eyes, as in _C. mesomelas, C. aureus,_
and (judging from Colonel H. Smith’s drawing) in _C. alopex,_ and
_C. thaleb._ Other species have a trace of a black line over the
corners of the eyes, as in _C. variegatus, cinereo-variegatus,_ and
_fulvus,_ and the wild Dingo. Hence I am inclined to conclude that
a tendency for tan-coloured spots to appear over the eyes in the
various breeds of dogs, is analogous to the case observed by
Desmarest, namely, that when any white appears on a dog the tip of
the tail is always white, “de manière à rappeler la tache terminale
de même couleur, qui caractérise la plupart des Canidés
sauvages.”[41] This rule, however, as I am assured by Mr. Jesse,
does not invariably hold good.
It has been objected that our domestic dogs cannot be descended
from wolves or jackals, because their periods of gestation are
different. The supposed difference rests on statements made by
Buffon, Gilibert, Bechstein, and others; but these are now known to
be erroneous; and the period is found to agree in the wolf, jackal,
and dog, as closely as could be expected, for it is often in some
degree variable.[42] Tessier, who has closely attended to this
subject, allows a difference of four days in the gestation of the
dog. The Rev. W. D. Fox has given me three carefully recorded cases
of retrievers, in which the bitch was put only once to the dog; and
not counting this day, but counting that of parturition, the
periods were fifty-nine, sixty-two, and sixty-seven days. The
average period is sixty-three days; but Bellingeri states that this
applies only to large dogs; and that for small races it is from
sixty to sixty-three days; Mr. Eyton of Eyton, who has had much
experience with dogs, also informs me that the time is apt to be
longer with large than with small dogs.
F. Cuvier has objected that the jackal would not have been
domesticated on account of its offensive smell; but savages are not
sensitive in this respect. The degree of odour, also, differs in
the different kinds of jackal;[43] and Colonel H. Smith makes a
sectional division of the group with one character dependent on not
being offensive. On the other hand, dogs— for instance, rough and
smooth terriers—differ much in this respect; and M. Godron states
that the hairless so-called Turkish dog is more odoriferous than
other dogs. Isidore Geoffroy[44] gave to a dog the same odour as
that from a jackal by feeding it on raw flesh.
The belief that our dogs are descended from wolves, jackals, South
American Canidæ, and other species, suggests a far more important
difficulty. These animals in their undomesticated state, judging
from a widely-spread analogy, would have been in some degree
sterile if intercrossed; and such sterility will be admitted as
almost certain by all those who believe that the lessened fertility
of crossed forms is an infallible criterion of specific
distinctness. Anyhow these animals keep distinct in the countries
which they inhabit in common. On the other hand, all domestic dogs,
which are here supposed to be descended from several distinct
species, are, as far as is known, mutually fertile together. But,
as Broca has well remarked,[45] the fertility of successive
generations of mongrel dogs has never been scrutinised with that
care which is thought indispensable when species are crossed. The
few facts leading to the conclusion that the sexual feelings and
reproductive powers differ in the several races of the dog when
crossed are (passing over mere size as rendering propagation
difficult) as follows: the Mexican Alco[46] apparently dislikes
dogs of other kinds, but this perhaps is not strictly a sexual
feeling; the hairless endemic dog of Paraguay, according to
Rengger, mixes less with the European races than these do with each
other; the Spitz dog in Germany is said to receive the fox more
readily than do other breeds; and Dr. Hodgkin states that a female
Dingo in England attracted the male wild foxes. If these latter
statements can be trusted, they prove some degree of sexual
difference in the breeds of the dog. But the fact remains that our
domestic dogs, differing so widely as they do in external
structure, are far more fertile together than we have reason to
believe their supposed wild parents would have been. Pallas
assumes[47] that a long course of domestication eliminates that
sterility which the parent-species would have exhibited if only
lately captured; no distinct facts are recorded in support of this
hypothesis; but the evidence seems to me so strong (independently
of the evidence derived from other domesticated animals) in favour
of our domestic dogs having descended from several wild stocks,
that I am inclined to admit the truth of this hypothesis.
There is another and closely allied difficulty consequent on the
doctrine of the descent of our domestic dogs from several wild
species, namely, that they do not seem to be perfectly fertile with
their supposed parents. But the experiment has not been quite
fairly tried; the Hungarian dog, for instance, which in external
appearance so closely resembles the European wolf, ought to be
crossed with this wolf: and the pariah dogs of India with Indian
wolves and jackals; and so in other cases. That the sterility is
very slight between certain dogs and wolves and other Canidæ is
shown by savages taking the trouble to cross them. Buffon got four
successive generations from the wolf and dog, and the mongrels were
perfectly fertile together.[48] But more lately M. Flourens states
positively as the result of his numerous experiments that hybrids
from the wolf and dog, crossed _inter se,_ become sterile at the
third generation, and those from the jackal and dog at the fourth
generation.[49] But these animals were closely confined; and many
wild animals, as we shall see in a future chapter, are rendered by
confinement in some degree or even utterly sterile. The Dingo,
which breeds freely in Australia with our imported dogs, would not
breed though repeatedly crossed in the Jardin des Plantes.[50] Some
hounds from Central Africa, brought home by Major Denham, never
bred in the Town of London;[51] and a similar tendency to sterility
might be transmitted to the hybrid offspring of a wild animal.
Moreover, it appears that in M. Flourens’ experiments the hybrids
were closely bred in and in for three or four generations; and this
circumstance would most certainly increase the tendency to
sterility. Several years ago I saw confined in the Zoological
Gardens of London a female hybrid from an English dog and jackal,
which even in this the first generation was so sterile that, as I
was assured by her keeper, she did not fully exhibit her proper
periods; but this case was certainly exceptional, as numerous
instances have occurred of fertile hybrids from these two animals.
In almost all experiments on the crossing of animals there are so
many causes of doubt, that it is extremely difficult to come to any
positive conclusion. It would, however, appear, that those who
believe that our dogs are descended from several species will have
not only to admit that their offspring after a long course of
domestication generally lose all tendency to sterility when crossed
together; but that between certain breeds of dogs and some of their
supposed aboriginal parents a certain degree of sterility has been
retained or possibly even acquired.
Notwithstanding the difficulties in regard to fertility given in the
last two paragraphs, when we reflect on the inherent improbability of
man having domesticated throughout the world one single species alone
of so widely distributed, so easily tamed, and so useful a group as the
Canidæ; when we reflect on the extreme antiquity of the different
breeds; and especially when we reflect on the close similarity, both in
external structure and habits, between the domestic dogs of various
countries and the wild species still inhabiting these same countries,
the balance of evidence is strongly in favour of the multiple origin of
our dogs.
_Differences between the several Breeds of the Dog.—_If the several
breeds have descended from several wild stocks, their difference
can obviously in part be explained by that of their parent species.
For instance, the form of the greyhound may be partly accounted for
by descent from some such animal as the slim Abyssinian _Canis
simensis,_[52] with its elongated muzzle; that of the larger dogs
from the larger wolves, and the smaller and slighter dogs from the
jackals: and thus perhaps we may account for certain constitutional
and climatal differences. But it would be a great error to suppose
that there has not been in addition[53] a large amount of
variation. The intercrossing of the several aboriginal wild stocks,
and of the subsequently formed races, has probably increased the
total number of breeds, and, as we shall presently see, has greatly
modified some of them. But we cannot explain by crossing the origin
of such extreme forms as thoroughbred greyhounds, bloodhounds,
bulldogs, Blenheim spaniels, terriers, pugs, etc., unless we
believe that forms equally or more strongly characterised in these
different respects once existed in nature. But hardly any one has
been bold enough to suppose that such unnatural forms ever did or
could exist in a wild state. When compared with all known members
of the family of Canidæ they betray a distinct and abnormal origin.
No instance is on record of such dogs as bloodhounds, spaniels,
true greyhounds having been kept by savages: they are the product
of long-continued civilisation.
The number of breeds and sub-breeds of the dog is great; Youatt for
instance, describes twelve kinds of greyhounds. I will not attempt
to enumerate or describe the varieties, for we cannot discriminate
how much of their difference is due to variation, and how much to
descent from different aboriginal stocks. But it may be worth while
briefly to mention some points. Commencing with the skull, Cuvier
has admitted[54] that in form the differences are “plus fortes que
celles d’aucunes espèces sauvages d’un même genre naturel.” The
proportions of the different bones; the curvature of the lower jaw,
the position of the condyles with respect to the plane of the teeth
(on which F. Cuvier founded his classification), and in mastiffs
the shape of its posterior branch; the shape of the zygomatic arch,
and of the temporal fossae; the position of the occiput—all vary
considerably.[55] The difference in size between the brains of dogs
belonging to large and small breeds “is something prodigious.”
“Some dogs’ brains are high and rounded, while others are low,
long, and narrow in front.” In the latter, “the olfactory lobes are
visible for about half their extent, when the brain is seen from
above, but they are wholly concealed by the hemispheres in other
breeds.”[56] The dog has properly six pairs of molar teeth in the
upper jaw, and seven in the lower; but several naturalists have
seen not rarely an additional pair in the upper jaw;[57] and
Professor Gervais says that there are dogs “qui ont sept paires de
dents supérieures et huit inférieures.” De Blainville[58] has given
full particulars on the frequency of these deviations in the number
of the teeth, and has shown that it is not always the same tooth
which is supernumerary. In short-muzzled races, according to H.
Müller,[59] the molar teeth stand obliquely, whilst in long-muzzled
races they are placed longitudinally, with open spaces between
them. The naked, so-called Egyptian or Turkish dog is extremely
deficient in its teeth,[60] —sometimes having none except one molar
on each side; but this, though characteristic of the breed, must be
considered as a monstrosity. M. Girard,[61] who seems to have
attended closely to the subject, says that the period of the
appearance of the permanent teeth differs in different dogs, being
earlier in large dogs; thus the mastiff assumes its adult teeth in
four or five months, whilst in the spaniel the period is sometimes
more than seven or eight months. On the other hand small dogs are
mature, and the females have arrived at the best age for breeding,
when one year old, whereas large dogs “are still in their puppyhood
at this time, and take fully twice as long to develop their
proportions.”[62]
With respect to minor differences little need be said. Isidore
Geoffroy has shown[63] that in size some dogs are six times as long
(the tail being excluded) as others; and that the height relatively
to the length of the body varies from between one to two, and one
to nearly four. In the Scotch deer-hound there is a striking and
remarkable difference in the size of the male and female.[64] Every
one knows how the ears vary in size in different breeds, and with
their great development their muscles become atrophied. Certain
breeds of dogs are described as having a deep furrow between the
nostrils and lips. The caudal vertebrae, according to F. Cuvier, on
whose authority the two last statements rest, vary in number; and
the tail in English cattle and some shepherd dogs is almost absent.
The mammae vary from seven to ten in number; Daubenton, having
examined twenty-one dogs, found eight with five mammae on each
side; eight with four on each side; and the others with an unequal
number on the two sides.[65] Dogs have properly five toes in front
and four behind, but a fifth toe is often added; and F. Cuvier
states that, when a fifth toe is present, a fourth cuneiform bone
is developed; and, in this case, sometimes the great cuneiform bone
is raised, and gives on its inner side a large articular surface to
the astragalus; so that even the relative connection of the bones,
the most constant of all characters, varies. These modifications,
however, in the feet of dogs are not important, because they ought
to be ranked, as De Blainville has shown[66] as monstrosities.
Nevertheless they are interesting from being correlated with the
size of the body, for they occur much more frequently with mastiffs
and other large breeds than with small dogs. Closely allied
varieties, however, sometimes differ in this respect; thus Mr.
Hodgson states that the black-and-tan Lassa variety of the Thibet
mastiff has the fifth digit, whilst the Mustang sub-variety is not
thus characterised. The extent to which the skin is developed
between the toes varies much; but we shall return to this point.
The degree to which the various breeds differ in the perfection of
their senses, dispositions, and inherited habits is notorious to
every one. The breeds present some constitutional differences: the
pulse, says Youatt[67] “varies materially according to the breed,
as well as to the size of the animal.” Different breeds of dogs are
subject in different degrees to various diseases. They certainly
become adapted to different climates under which they have long
existed. It is notorious that most of our best European breeds
deteriorate in India.[68] The Rev R. Everest[69] believes that no
one has succeeded in keeping the Newfoundland dog long alive in
India; so it is, according to Lichtenstein,[70] even at the Cape of
Good Hope. The Thibet mastiff degenerates on the plains of India,
and can live only on the mountains.[71] Lloyd[72] asserts that our
bloodhounds and bulldogs have been tried, and cannot withstand the
cold of the northern European forests.
Seeing in how many characters the races of the dog differ from each
other, and remembering Cuvier’s admission that their skulls differ
more than do those of the species of any natural genus, and bearing
in mind how closely the bones of wolves, jackals, foxes, and other
Canidæ agree, it is remarkable that we meet with the statement,
repeated over and over again, that the races of the dog differ in
no important characters. A highly competent judge, Prof.
Gervais,[73] admits “si l’on prenait sans contrôle les alterations
dont chacun de ces organes est susceptible, on pourrait croire
qu’il y a entre les chiens domestiques des différences plus grandes
que celles qui séparent ailleurs les espèces, quelquefois même les
genres.” Some of the differences above enumerated are in one
respect of comparatively little value, for they are not
characteristic of distinct breeds: no one pretends that such is the
case with the additional molar teeth or with the number of mammae;
the additional digit is generally present with mastiffs, and some
of the more important differences in the skull and lower jaw are
more or less characteristic of various breeds. But we must not
forget that the predominant power of selection has not been applied
in any of these cases; we have variability in important parts, but
the differences have not been fixed by selection. Man cares for the
form and fleetness of his greyhounds, for the size of his mastiffs,
and formerly for the strength of the jaw in his bulldogs, etc.; but
he cares nothing about the number of their molar teeth or mammae or
digits; nor do we know that differences in these organs are
correlated with, or owe their development to, differences in other
parts of the body about which man does care. Those who have
attended to the subject of selection will admit that, nature having
given variability, man, if he so chose, could fix five toes to the
hinder feet of certain breeds of dogs, as certainly as to the feet
of his Dorking fowls: he could probably fix, but with much more
difficulty, an additional pair of molar teeth in either jaw, in the
same way as he has given additional horns to certain breeds of
sheep; if he wished to produce a toothless breed of dogs, having
the so-called Turkish dog with its imperfect teeth to work on, he
could probably do so, for he has succeeded in making hornless
breeds of cattle and sheep.
With respect to the precise causes and steps by which the several
races of dogs have come to differ so greatly from each other, we
are, as in most other cases, profoundly ignorant. We may attribute
part of the difference in external form and constitution to
inheritance from distinct wild stocks, that is to changes effected
under nature before domestication. We must attribute something to
the crossing of the several domestic and natural races. I shall,
however, soon recur to the crossing of races. We have already seen
how often savages cross their dogs with wild native species; and
Pennant gives a curious account[74] of the manner in which
Fochabers, in Scotland, was stocked “with a multitude of curs of a
most wolfish aspect” from a single hybrid-wolf brought into that
district.
It would appear that climate to a certain extent directly modifies
the forms of dogs. We have lately seen that several of our English
breeds cannot live in India, and it is positively asserted that
when bred there for a few generations they degenerate not only in
their mental faculties, but in form. Captain Williamson,[75] who
carefully attended to this subject, states that “hounds are the
most rapid in their decline;” “greyhounds and pointers, also,
rapidly decline.” But spaniels, after eight or nine generations,
and without a cross from Europe, are as good as their ancestors.
Dr. Falconer informs me that bulldogs, which have been known, when
first brought into the country, to pin down even an elephant by its
trunk, not only fall off after two or three generations in pluck
and ferocity, but lose the under-hung character of their lower
jaws; their muzzles become finer and their bodies lighter. English
dogs imported into India are so valuable that probably due care has
been taken to prevent their crossing with native dogs; so that the
deterioration cannot be thus accounted for. The Rev. R. Everest
informs me that he obtained a pair of setters, born in India, which
perfectly resembled their Scotch parents: he raised several litters
from them in Delhi, taking the most stringent precautions to
prevent a cross, but he never succeeded, though this was only the
second generation in India, in obtaining a single young dog like
its parents in size or make; their nostrils were more contracted,
their noses more pointed, their size inferior, and their limbs more
slender. So again on the coast of Guinea, dogs, according to
Bosman, “alter strangely; their ears grow long and stiff like those
of foxes, to which colour they also incline, so that in three or
four years, they degenerate into very ugly creatures; and in three
or four broods their barking turns into a howl.”[76] This
remarkable tendency to rapid deterioration in European dogs
subjected to the climate of India and Africa, may be largely
accounted for by reversion to a primordial condition which many
animals exhibit, as we shall hereafter see, when their
constitutions are in any way disturbed.
Some of the peculiarities characteristic of the several breeds of
the dog have probably arisen suddenly, and, though strictly
inherited, may be called monstrosities; for instance, the shape of
the legs and body in the turnspit of Europe and India; the shape of
the head and the under-hanging jaw in the bull-and pug-dog, so
alike in this one respect and so unlike in all others. A
peculiarity suddenly arising, and therefore in one sense deserving
to be called a monstrosity, may, however, be increased and fixed by
man’s selection. We can hardly doubt that long-continued training,
as with the greyhound in coursing hares, as with water-dogs in
swimming—and the want of exercise, in the case of lapdogs—must have
produced some direct effect on their structure and instincts. But
we shall immediately see that the most potent cause of change has
probably been the selection, both methodical and unconscious, of
slight individual differences,—the latter kind of selection
resulting from the occasional preservation, during hundreds of
generations, of those individual dogs which were the most useful to
man for certain purposes and under certain conditions of life. In a
future chapter on Selection I shall show that even barbarians
attend closely to the qualities of their dogs. This unconscious
selection by man would be aided by a kind of natural selection; for
the dogs of savages have partly to gain their own subsistence: for
instance, in Australia, as we hear from Mr. Nind,[77] the dogs are
sometimes compelled by want to leave their masters and provide for
themselves; but in a few days they generally return. And we may
infer that dogs of different shapes, sizes, and habits, would have
the best chance of surviving under different circumstances,—on open
sterile plains, where they have to run down their own prey,—on
rocky coasts, where they have to feed on crabs and fish left in the
tidal pools, as in the case of New Guinea and Tierra del Fuego. In
this latter country, as I am informed by Mr. Bridges, the Catechist
to the Mission, the dogs turn over the stones on the shore to catch
the crustaceans which lie beneath, and they “are clever enough to
knock off the shell-fish at a first blow;” for if this be not done,
shell-fish are well-known to have an almost invincible power of
adhesion.
It has already been remarked that dogs differ in the degree to
which their feet are webbed. In dogs of the Newfoundland breed,
which are eminently aquatic in their habits, the skin, according to
Isidore Geoffroy,[78] extends to the third phalanges whilst in
ordinary dogs it extends only to the second. In two Newfoundland
dogs which I examined, when the toes were stretched apart and
viewed on the under side, the skin extended in a nearly straight
line between the outer margins of the balls of the toes; whereas,
in two terriers of distinct sub-breeds, the skin viewed in the same
manner was deeply scooped out. In Canada there is a dog which is
peculiar to the country and common there, and this has “half-webbed
feet and is fond of the water.”[79] English otter-hounds are said
to have webbed feet: a friend examined for me the feet of two, in
comparison with the feet of some harriers and bloodhounds; he found
the skin variable in extent in all, but more developed in the
otter-hounds than in the others.[80] As aquatic animals which
belong to quite different orders have webbed feet, there can be no
doubt that this structure would be serviceable to dogs that
frequent the water. We may confidently infer that no man ever
selected his water-dogs by the extent to which the skin was
developed between their toes; but what he does, is to preserve and
breed from those individuals which hunt best in the water, or best
retrieve wounded game, and thus he unconsciously selects dogs with
feet slightly better webbed. The effects of use from the frequent
stretching apart of the toes will likewise aid in the result. Man
thus closely imitates Natural Selection. We have an excellent
illustration of this same process in North America, where,
according to Sir J. Richardson,[81] all the wolves, foxes, and
aboriginal domestic dogs have their feet broader than in the
corresponding species of the Old World, and “well calculated for
running on the snow” Now, in these Arctic regions, the life or
death of every animal will often depend on its success in hunting
over the snow when soft; and this will in part depend on the feet
being broad; yet they must not be so broad as to interfere with the
activity of the animal when the ground is sticky, or with its power
of burrowing holes, or with other necessary habits of life.
As changes in domestic breeds which take place so slowly are not to
be noticed at any one period, whether due to the selection of
individual variations or of differences resulting from crosses, are
most important in understanding the origin of our domestic
productions, and likewise in throwing indirect light on the changes
effected under nature, I will give in detail such cases as I have
been able to collect. Lawrence,[82] who paid particular attention
to the history of the foxhound, writing in 1829, says that between
eighty and ninety years before “an entirely new foxhound was raised
through the breeder’s art,” the ears of the old southern hound
being reduced, the bone and bulk lightened, the waist increased in
length, and the stature somewhat added to. It is believed that this
was effected by a cross with a greyhound. With respect to this
latter dog, Youatt,[83] who is generally cautious in his
statements, says that the greyhound within the last fifty years,
that is before the commencement of the present century, “assumed a
somewhat different character from that which he once possessed. He
is now distinguished by a beautiful symmetry of form, of which he
could not once boast, and he has even superior speed to that which
he formerly exhibited. He is no longer used to struggle with deer,
but contends with his fellows over a shorter and speedier course.”
An able writer[84] believes that our English greyhounds are the
descendants, _progressively improved,_ of the large rough
greyhounds which existed in Scotland so early as the third century.
A cross at some former period with the Italian greyhound has been
suspected; but this seems hardly probable, considering the
feebleness of this latter breed. Lord Orford, as is well-known,
crossed his famous greyhounds, which failed in courage, with a
bulldog—this breed being chosen from being erroneously supposed to
be deficient in the power of scent; “after the sixth or seventh
generation,” says Youatt, “there was not a vestige left of the form
of the bulldog, but his courage and indomitable perseverance
remained.”
Youatt infers, from a comparison of an old picture of King
Charles’s spaniels with the living dog, that “the breed of the
present day is materially altered for the worse:” the muzzle has
become shorter, the forehead more prominent, and the eyes larger;
the changes in this case have probably been due to simple
selection. The setter, as this author remarks in another place, “is
evidently the large spaniel improved to his present peculiar size
and beauty, and taught another way of marking his game. If the form
of the dog were not sufficiently satisfactory on this point, we
might have recourse to history:” he then refers to a document dated
1685 bearing on this subject, and adds that the pure Irish setter
shows no signs of a cross with the pointer, which some authors
suspect has been the case with the English setter. The bulldog is
an English breed, and as I hear from Mr. G. R. Jesse,[85] seems to
have originated from the mastiff since the time of Shakspeare; but
certainly existed in 1631, as shown by Prestwick Eaton’s letters.
There can be no doubt that the fancy bulldogs of the present day,
now that they are not used for bull-baiting, have become greatly
reduced in size, without any express intention on the part of the
breeder. Our pointers are certainly descended from a Spanish breed,
as even their present names, Don, Ponto, Carlos, etc., show; it is
said that they were not known in England before the Revolution in
1688;[86] but the breed since its introduction has been much
modified, for Mr. Borrow, who is a sportsman and knows Spain
intimately well, informs me that he has not seen in that country
any breed “corresponding in figure with the English pointer; but
there are genuine pointers near Xeres which have been imported by
English gentlemen.” A nearly parallel case is offered by the
Newfoundland dog, which was certainly brought into England from
that country, but which has since been so much modified that, as
several writers have observed, it does not now closely resemble any
existing native dog in Newfoundland.[87]
These several cases of slow and gradual changes in our English dogs
possess some interest; for though the changes have generally, but not
invariably, been caused by one or two crosses with a distinct breed,
yet we may feel sure, from the well-known extreme variability of
crossed breeds, that rigorous and long-continued selection must have
been practised, in order to improve them in a definite manner. As soon
as any strain or family became slightly improved or better adapted to
alter circumstances, it would tend to supplant the older and less
improved strains. For instance, as soon as the old foxhound was
improved by a cross with the greyhound, or by simple selection, and
assumed its present character—and the change was probably desired owing
to the increased fleetness of our hunters—it rapidly spread throughout
the country, and is now everywhere nearly uniform. But the process of
improvement is still going on for every one tries to improve his strain
by occasionally procuring dogs from the best kennels. Through this
process of gradual substitution the old English hound has been lost;
and so it has been with the Irish wolf-dog, the old English bulldog,
and several other breeds, such as the alaunt, as I am informed by Mr.
Jesse. But the extinction of former breeds is apparently aided by
another cause; for whenever a breed is kept in scanty numbers, as at
present with the bloodhound, it is reared with some difficulty,
apparently from the evil effects of long-continued close interbreeding.
As several breeds of the dog have been slightly but sensibly modified
within so short a period as the last one or two centuries, by the
selection of the best individuals, modified in many cases by crosses
with other breeds; and as we shall hereafter see that the breeding of
dogs was attended to in ancient times, as it still is by savages, we
may conclude that we have in selection, even if only occasionally
practised, a potent means of modification.
DOMESTIC CATS.
Cats have been domesticated in the East from an ancient period; Mr.
Blyth informs me that they are mentioned in a Sanskrit writing 2000
years old, and in Egypt their antiquity is known to be even
greater, as shown by monumental drawings and their mummied bodies.
These mummies, according to De Blainville,[88] who has particularly
studied the subject, belong to no less than three species, namely,
_F. caligulata,_ bubastes, and _chaus._ The two former species are
said to be still found, both wild and domesticated, in parts of
Egypt. _F. caligulata_ presents a difference in the first inferior
milk molar tooth, as compared with the domestic cats of Europe,
which makes De Blainville conclude that it is not one of the
parent-forms of our cats. Several naturalists, as Pallas, Temminck,
Blyth, believe that domestic cats are the descendants of several
species commingled: it is certain that cats cross readily with
various wild species, and it would appear that the character of the
domestic breeds has, at least in some cases, been thus affected.
Sir W. Jardine has no doubt that, “in the north of Scotland, there
has been occasional crossing with our native species (_F.
sylvestris_), and that the result of these crosses has been kept in
our houses. I have seen,” he adds, “many cats very closely
resembling the wild cat, and one or two that could scarcely be
distinguished from it.” Mr. Blyth[89] remarks on this passage, “but
such cats are never seen in the southern parts of England; still,
as compared with any Indian tame cat, the affinity of the ordinary
British cat to _F. sylvestris_ is manifest; and due I suspect to
frequent intermixture at a time when the tame cat was first
introduced into Britain and continued rare, while the wild species
was far more abundant than at present.” In Hungary, Jeitteles[90]
was assured on trustworthy authority that a wild male cat crossed
with a female domestic cat, and that the hybrids long lived in a
domesticated state. In Algiers the domestic cat has crossed with
the wild cat (_F. lybica_) of that country.[91] In South Africa as
Mr. E. Layard informs me, the domestic cat intermingles freely with
the wild _F. caffra_; he has seen a pair of hybrids which were
quite tame and particularly attached to the lady who brought them
up; and Mr. Fry has found that these hybrids are fertile. In India
the domestic cat, according to Mr. Blyth, has crossed with four
Indian species. With respect to one of these species, _F. chaus,_
an excellent observer, Sir W. Elliot, informs me that he once
killed, near Madras, a wild brood, which were evidently hybrids
from the domestic cat; these young animals had a thick lynx-like
tail and the broad brown bar on the inside of the forearm
characteristic of _F. chaus._ Sir W. Elliot adds that he has often
observed this same mark on the forearms of domestic cats in India.
Mr. Blyth states that domestic cats coloured nearly like _ F.
chaus,_ but not resembling that species in shape, abound in Bengal;
he adds, “such a colouration is utterly unknown in European cats,
and the proper tabby markings (pale streaks on a black ground,
peculiarly and symmetrically disposed), so common in English cats,
are never seen in those of India.” Dr. D. Short has assured Mr.
Blyth[92] that, at Hansi, hybrids between the common cat and _F.
ornata_ (or _ torquata_) occur, “and that many of the domestic cats
of that part of India were undistinguishable from the wild _F.
ornata._” Azara states, but only on the authority of the
inhabitants, that in Paraguay the cat has crossed with two native
species. From these several cases we see that in Europe, Asia,
Africa, and America, the common cat, which lives a freer life than
most other domesticated animals, has crossed with various wild
species; and that in some instances the crossing has been
sufficiently frequent to affect the character of the breed.
Whether domestic cats have descended from several distinct species, or
have only been modified by occasional crosses, their fertility, as far
as is known, is unimpaired. The large Angora or Persian cat is the most
distinct in structure and habits of all the domestic breeds; and is
believed by Pallas, but on no distinct evidence, to be descended from
the _F. manul_ of middle Asia; and I am assured by Mr. Blyth that the
Angora cat breeds freely with Indian cats, which, as we have already
seen, have apparently been much crossed with _F. chaus._ In England
half-bred Angora cats are perfectly fertile with one another.
Within the same country we do not meet with distinct races of the
cat, as we do of dogs and of most other domestic animals; though
the cats of the same country present a considerable amount of
fluctuating variability. The explanation obviously is that, from
their nocturnal and rambling habits, indiscriminate crossing cannot
without much trouble be prevented. Selection cannot be brought into
play to produce distinct breeds, or to keep those distinct which
have been imported from foreign lands. On the other hand, in
islands and in countries completely separated from each other, we
meet with breeds more or less distinct; and these cases are worth
giving, showing that the scarcity of distinct races in the same
country is not caused by a deficiency of variability in the animal.
The tailless cats of the Isle of Man are said to differ from common
cats not only in the want of a tail, but in the greater length of
their hind legs, in the size of their heads, and in habits. The
Creole cat of Antigua, as I am informed by Mr. Nicholson, is
smaller, and has a more elongated head, than the British cat. In
Ceylon, as Mr. Thwaites writes to me, every one at first notices
the different appearance of the native cat from the English animal;
it is of small size, with closely lying hairs; its head is small,
with a receding forehead; but the ears are large and sharp;
altogether it has what is there called a “low-caste” appearance.
Rengger[93] says that the domestic cat, which has been bred for 300
years in Paraguay, presents a striking difference from the European
cat; it is smaller by a fourth, has a more lanky body, its hair is
short, shining, scanty and lies close, especially on the tail: he
adds that the change has been less at Ascension, the capital of
Paraguay, owing to the continual crossing with newly imported cats;
and this fact well illustrates the importance of separation. The
conditions of life in Paraguay appear not to be highly favourable
to the cat, for, though they have run half-wild, they do not become
thoroughly feral, like so many other European animals. In another
part of South America, according to Roulin,[94] the introduced cat
has lost the habit of uttering its hideous nocturnal howl. The Rev.
W.D. Fox purchased a cat in Portsmouth, which he was told came from
the coast of Guinea; its skin was black and wrinkled, fur
bluish-grey and short, its ears rather bare, legs long, and whole
aspect peculiar. This “negro” cat was fertile with common cats. On
the opposite coast of Africa, at Mombas, Captain Owen, R.N.,[95]
states that all the cats are covered with short stiff hair instead
of fur: he gives a curious account of a cat from Algoa Bay, which
had been kept for some time on board and could be identified with
certainty; this animal was left for only eight weeks at Mombas, but
during that short period it “underwent a complete metamorphosis,
having parted with its sandy-coloured fur.” A cat from the Cape of
Good Hope has been described by Desmarest as remarkable from a red
stripe extending along the whole length of its back. Throughout an
immense area, namely, the Malayan archipelago, Siam, Pegu, and
Burmah, all the cats have truncated tails about half the proper
length,[96] often with a sort of knot at the end. In the Caroline
archipelago the cats have very long legs, and are of a
reddish-yellow colour.[97] In China a breed has drooping ears. At
Tobolsk, according to Gmelin, there is a red-coloured breed. In
Asia, also, we find the well-known Angora or Persian breed.
The domestic cat has run wild in several countries, and everywhere
assumes, as far as can be judged by the short recorded
descriptions, a uniform character. Near Maldonado, in La Plata, I
shot one which seemed perfectly wild; it was carefully examined by
Mr. Waterhouse,[98] who found nothing remarkable in it, excepting
its great size. In New Zealand according to Dieffenbach, the feral
cats assume a streaky grey colour like that of wild cats; and this
is the case with the half-wild cats of the Scotch Highlands.
We have seen that distant countries possess distinct domestic races of
the cat. The differences may be in part due to descent from several
aboriginal species, or at least to crosses with them. In some cases, as
in Paraguay, Mombas, and Antigua, the differences seem due to the
direct action of different conditions of life. In other cases some
slight effect may possibly be attributed to natural selection, as cats
in many cases have largely to support themselves and to escape diverse
dangers. But man, owing to the difficulty of pairing cats, has done
nothing by methodical selection; and probably very little by
unintentional selection; though in each litter he generally saves the
prettiest, and values most a good breed of mouse- or rat-catchers.
Those cats which have a strong tendency to prowl after game, generally
get destroyed by traps. As cats are so much petted, a breed bearing the
same relation to other cats, that lapdogs bear to larger dogs, would
have been much valued; and if selection could have been applied, we
should certainly have had many breeds in each long-civilised country,
for there is plenty of variability to work upon.
We see in this country considerable diversity in size, some in the
proportions of the body, and extreme variability in colouring. I
have only lately attended to this subject, but have already heard
of some singular cases of variation; one of a cat born in the West
Indies toothless, and remaining so all its life. Mr. Tegetmeier has
shown me the skull of a female cat with its canines so much
developed that they protruded uncovered beyond the lips; the tooth
with the fang being .95, and the part projecting from the gum .6 of
an inch in length. I have heard of several families of six-toed
cats, in one of which the peculiarity had been transmitted for at
least three generations. The tail varies greatly in length; I have
seen a cat which always carried its tail flat on its back when
pleased. The ears vary in shape, and certain strains, in England,
inherit a pencil-like tuft of hairs, above a quarter of an inch in
length, on the tips of their ears; and this same peculiarity,
according to Mr. Blyth, characterises some cats in India. The great
variability in the length of the tail and the lynx-like tufts of
hairs on the ears are apparently analogous to differences in
certain wild species of the genus. A much more important
difference, according to Daubenton,[99] is that the intestines of
domestic cats are wider, and a third longer, than in wild cats of
the same size; and this apparently has been by their less strictly
carnivorous diet.
REFERENCES
[1] Owen ‘British Fossil Mammals,’ pp. 123 to 133. Pictet’s ‘Traité de
Pal.,’ 1853, tom. i. p. 202. De Blainville in his ‘Ostéographie,
Canidæ,’ p. 142, has largely discussed the whole subject, and
concludes that the extinct parent of all domesticated dogs came
nearest to the wolf in organisation, and to the jackal in habits. _See
also_ Boyd Dawkins, ‘Cave Hunting,’ 1874, p. 131, etc., and his other
publications. Jeitteles has discussed in great detail the character of
the breeds of pre-historic dogs: ‘Die vorgeschichtlichen Alterthümer
der Stadt Olmütz,’ II. Theil, 1872, p. 44 to end.
[2] Pallas, I believe, originated this doctrine in ‘Act. Acad. St.
Petersburgh,’ 1780, Part ii. Ehrenberg has advocated it, as may be
seen in De Blainville’s ‘Ostéographie,’ p. 79. It has been carried to
an extreme extent by Col. Hamilton Smith in the ‘Naturalist Library,’
vols ix and x. Mr. W. C. Martin adopts it in his excellent ‘History of
the Dog,’ 1845; as does Dr. Morton, as well as Nott and Gliddon, in
the United States. Prof. Low, in his ‘Domesticated Animals,’ 1845, p.
666, comes to this same conclusion. No one has argued on this side
with more clearness and force than the late James Wilson, of
Edinburgh, in various papers read before the Highland Agricultural and
Wernerian Societies. Isidore Geoffroy Saint-Hilaire (‘Hist. Nat.
Gén.,’ 1860, tom. iii. p. 107), though he believes that most dogs have
descended from the jackal, yet inclines to the belief that some are
descended from the wolf. Prof. Gervais (‘Hist. Nat. Mamm.’ 1855, tom.
ii. p. 69, referring to the view that all the domestic races are the
modified descendants of a single species, after a long discussion,
says, “Cette opinion est, suivant nous du moins, la moins probable.”
[3] Berjeau, ‘The Varieties of the Dog; in old Sculptures and
Pictures,’ 1863. ‘Der Hund,’ von Dr. F. L. Walther, Giessen, 1817, s.
48: this author seems carefully to have studied all classical works on
the subject. _See also_ Volz, ‘Beiträge zur Kulturgeschichte,’
Leipzig, 1852, s. 115, ‘Youatt on the Dog,’ 1845, p. 6. A very full
history is given by De Blainville in his ‘Ostéographie, Canidæ.’
[4] I have seen drawings of this dog from the tomb of the son of Esar
Haddon, and clay models in the British Museum. Nott and Gliddon, in
their ‘Types of Mankind,’ 1854, p. 393, give a copy of these drawings.
This dog has been called a Thibetan mastiff, but Mr. H. A. Oldfield,
who is familiar with the so-called Thibet mastiff, and has examined
the drawings in the British Museum, informs me that he considers them
different.
[5] ‘Proc. Zoolog. Soc.,’ July 12th, 1831.
[6] ‘Sporting in Algeria,’ p. 51.
[7] Berjeau gives facsimiles of the Egyptian drawings. Mr. C. L.
Martin in his ‘History of the Dog,’ 1845, copies several figures from
the Egyptian monuments, and speaks with much confidence with respect
to their identity with still living dogs. Messrs. Nott and Gliddon
(‘Types of Mankind,’ 1854, p. 388) give still more numerous figures.
Mr. Gliddon asserts that a curl-tailed greyhound, like that
represented on the most ancient monuments, is common in Borneo; but
the Rajah, Sir J. Brooke, informs me that no such dog exists there.
[8] These, and the following facts on the Danish remains, are taken
from M. Morlot’s most interesting memoir in ‘Soc. Vaudoise des Sc.
Nat.’ tom. vi., 1860, pp. 281, 299, 320.
[9] ‘Die Fauna der Pfahlbauten,’ 1861, s. 117, 162.
[10] De Blainville ‘Ostéographie, Canidæ.’
[11] Sir R. Schomburgk has given me information on this head. _See
also_ ‘Journal of R. Geographical Soc.’ vol. xiii. 1843, p. 65.
[12] ‘Domestication of Animals:’ Ethnological Soc., Dec. 22nd, 1863.
[13] ‘Journal of Researches,’ etc., 1845, p. 393. With respect to
_Canis antarcticus, see_ p. 193. For the case of the antelope, _see_
‘Journal Royal Geograph. Soc.,’ vol. xxiii. p. 94.
[14] The authorities for the foregoing statements are as
follow:—Richardson in ‘Fauna Boreali-Americana,’ 1829, pp. 64, 75; Dr.
Kane ‘Arctic Explorations,’ 1856, vol. i. pp. 398, 455; Dr. Hayes
‘Arctic Boat Journey,’ 1860, p. 167. Franklin’s ‘Narrative,’ vol. i.
p. 269, gives the case of three whelps of a black wolf being carried
away by the Indians. Parry, Richardson, and others, give accounts of
wolves and dogs naturally crossing in the eastern parts of North
America. Seeman in his ‘Voyage of H.M.S. _Herald_,’ 1853, vol. ii. p.
26, says the wolf is often caught by the Esquimaux for the purpose of
crossing with their dogs, and thus adding to their size and strength.
M. Lamare-Picquot in ‘Bull. de la Soc. d’Acclimat,’ tom. vii., 1860,
p. 148, gives a good account of the half-bred Esquimaux dogs.
[15] ‘Fauna Boreali-Americana,’ 1829, pp. 73, 78, 80. Nott and
Gliddon, ‘Types of Mankind,’ p. 383. The naturalist and traveller
Bartram is quoted by Hamilton Smith, in ‘Naturalist Lib.,’ vol. x. p.
156. A Mexican domestic dog seems also to resemble a wild dog of the
same country; but this may be the prairie-wolf. Another capable judge,
Mr. J. K. Lord (‘The Naturalist in Vancouver Island,’ 1866, vol. ii.
p. 218), says that the Indian dog of the Spokans, near the Rocky
Mountains, “is beyond all question nothing more than a tamed Cayote or
prairie-wolf,” or _Canis latrans._)
[16] I quote this from Mr. R. Hill’s excellent account of the Alco or
domestic dog of Mexico, in Gosse’s ‘Naturalist’s Sojourn in Jamaica,’
1851, p. 329.
[17] ‘Naturgeschichte der Säugethiere von Paraguay,’ 1830, s. 151.
[18] Quoted in Humboldt’s ‘Aspects of Nature’ (Eng. trans.), vol. i.
p. 108.
[19] p.t’s ‘Travels in Hungary and Transylvania,’ vol. i. p. 501.
Jeitteles ‘Fauna Hungariæ Superioris,’ 1862, s. 13. _See_ Pliny ‘Hist.
of the World’ (Eng. trans.), 8th book, ch. xl., about the Gauls
crossing their dogs. _See also_ Aristotle ‘Hist. Animal.’lib. viii. c.
28. For good evidence about wolves and dogs naturally crossing near
the Pyrenees, _see_ M. Mauduyt ‘Du Loup et de ses Races,’ Poitiers,
1851; also Pallas in ‘Acta Acad. St. Petersburgh,’ 1780, part ii. p.
94.
[20] I give this on excellent authority, namely Mr. Blyth (under the
signature of Zoophilus), in the ‘Indian Sporting Review,’ Oct. 1856,
p. 134. Mr. Blyth states that he was struck with the resemblance
between a brush-tailed race of pariah-dogs, north-west of Cawnpore,
and the Indian wolf. He gives corroborative evidence with respect to
the dogs of the valley of the Nerbudda.
[21] For numerous and interesting details on the resemblance of dogs
and jackals _see_ Isid. Geoffroy St.-Hilaire ‘Hist. Nat. Gén.,’ 1860,
tom. iii. p. 101. _ See also_ ‘Hist. Nat. des Mammifères,’ par Prof.
Gervais, 1855, tom. ii. p. 60.
[22] Also Güldenstädt ‘Nov. Comment. Acad. Petrop.,’ tom. xx., pro
anno 1775, p. 449. Also Salvin in ‘Land and Water,’ Oct. 1869.
[23] Quoted by De Blainville in his ‘Ostéographie, Canidæ,’ pp. 79,
98.
[24] _See_ Pallas in ‘Act. Acad. St. Petersburgh,’ 1780, part ii. p.
91. For Algeria, _see_ Isid. Geoffroy St.-Hilaire ‘Hist. Nat. Gén.,’
tom. iii. p. 177. In both countries it is the male jackal which pairs
with female domestic dogs.
[25] John Barbut’s ‘Description of the Coast of Guinea in 1746.’
[26] ‘Travels in South Africa,’ vol. ii. p. 272.
[27] Selwyn, Geology of Victoria; ‘Journal of Geolog. Soc.,’ vol.
xiv., 1858, p. 536, and vol. xvi., 1860, p. 148; and Prof. M’Coy, in
‘Annals and Mag. of Nat. Hist.’ (3rd series) vol. ix., 1862, p. 147.
The Dingo differs from the dogs of the central Polynesian islands.
Dieffenbach remarks (‘Travels,’ vol. ii. p. 45) that the native New
Zealand dog also differs from the Dingo.
[28] These latter remarks afford, I think, a sufficient answer to some
criticisms by Mr. Wallace, on the multiple origin of dogs, given in
Lyell’s ‘Principles of Geology,’ 1872, vol. ii. p. 295.
[29] ‘Proceedings Zoolog. Soc.,’ 1833, p. 112. _ See also,_ on the
taming of the common wolf, L. Lloyd, ‘Scandinavian Adventures,’ 1854,
vol. i. p. 460. With respect to the jackal, _see_ Prof. Gervais ‘Hist.
Nat. Mamm.’ tom. ii. p. 61. With respect to the aguara of Paraguay
_see_ Rengger’s work.
[30] Roulin, in ‘Mém. présent. par divers Savans,’ tom. vi. p. 341.
[31] Martin, ‘History of the Dog,’ p. 14.
[32] Quoted by L. Lloyd in ‘Field Sports of North of Europe,’ vol. i.
p. 387.
[33] Quatrefages, ‘Soc. d’Acclimat.,’ May 11th, 1863, p. 7.
[34] ‘Annals and Mag. of Nat. Hist.’ vol. xv., 1845, p. 140.
[35] Azara, ‘Voyages dans l’Amér. Mérid.’ tom. i. p. 381; his account
is fully confirmed by Rengger. Quatrefages gives an account of a bitch
brought from Jerusalem to France which burrowed a hole and littered in
it. _ See_ ‘Discours, Exposition des Races Canines,’ 1865, p. 3.
[36] With respect to wolves burrowing holes _ see_ Richardson, ‘Fauna
Boreali-Americana,’ p. 64; and Bechstein ‘Naturgeschichte
Deutschlands,’ B. i. s. 617.
[37] _See_ Poeppig, ‘Reise in Chile,’ B. i. s. 290; Mr. G. Clarke, as
above; and Rengger, s. 155.
[38] Dogs, ‘Nat. Library,’ vol. x. p. 121; an endemic South American
dog seems also to have become feral in this island. _See_ Gosse’s
‘Jamaica,’ p. 340.
[39] Low ‘Domesticated Animals,’ p. 650.
[40] ‘The Naturalist Library,’ Dogs, vol. x. pp. 4, 19.
[41] Quoted by Prof. Gervais, ‘Hist. Nat. Mamm.,’ tom. ii. p. 66.
[42] J. Hunter shows that the long period of seventy-three days given
by Buffon is easily explained by the bitch having received the dog
many times during a period of sixteen days (‘Phil. Transact.,’ 1787,
p. 353). Hunter found that the gestation of a mongrel from wolf and
dog (‘Phil. Transact.,’ 1789, p. 160) apparently was sixty-three days,
for she received the dog more than once. The period of a mongrel dog
and jackal was fifty-nine days. Fred. Cuvier found the period of
gestation of the wolf to be (‘Dict. Class. d’Hist. Nat.’ tom. iv. p.
8) two months and a few days, which agrees with the dog. Isid G.
St.-Hilaire, who has discussed the whole subject, and from whom I
quote Bellingeri, states (‘Hist. Nat. Gén.,’ tom. iii. p. 112) that in
the Jardin des Plantes the period of the jackal has been found to be
from sixty to sixty-three days, exactly as with the dog.
[43] _See_ Isid. Geoffroy St.-Hilaire ‘Hist. Nat. Gén.,’ tom. iii. p.
112, on the odour of jackals. Col. Ham. Smith in ‘Nat. Lib.,’ vol. x.
p. 289.
[44] Quoted by Quatrefages in ‘Bull. Soc. d’Acclimat.,’ May 11th,
1863.
[45] ‘Journal de la Physiologie,’ tom. ii. p. 385.
[46] _See_ Mr. R. Hill’s excellent account of this breed in Gosse’s
‘Jamaica,’ p. 338; Rengger ‘Säugethiere von Paraguay,’ s. 153. With
respect to Spitz dogs, _see_ Bechstein’s ‘Naturgesch. Deutschlands,’
1801, B. i. s. 638. With respect to Dr. Hodgkin’s statement made
before Brit. Assoc. _see_ ‘The Zoologist,’ vol. iv. for 1845-46 p.
1097.
[47] ‘Acta Acad. St. Petersburgh,’ 1780, part ii. pp. 84, 100.
[48] M. Broca has shown (‘Journal de Physiologie,’ tom. ii. p. 353)
that Buffon’s experiments have been often misrepresented. Broca has
collected (pp. 390-395) many facts on the fertility of crossed dogs,
wolves, and jackals.
[49] ‘De la Longévité Humaine,’ par M. Flourens, 1855, p. 143. Mr.
Blyth says (‘Indian Sporting Review,’ vol. 2 p. 137) that he has seen
in India several hybrids from the pariah-dog and jackal; and between
one of these hybrids and a terrier. The experiments of Hunter on the
jackal are well-known. _See also_ Isid. Geoffroy St.-Hilaire, ‘Hist.
Nat. Gén.,’ tom. iii. p. 217, who speaks of the hybrid offspring of
the jackal as perfectly fertile for three generations.
[50] On authority of F. Cuvier quoted in Bronn’s ‘Geschichte der
Natur,’ B ii. s. 164.
[51] W. C. L. Martin ‘History of the Dog,’ 1845, p. 203. Mr. Philip P.
King, after ample opportunities of observation, informs me that the
Dingo and European dogs often cross in Australia.
[52] Rüppel ‘Neue Wirbelthiere von Abyssinien,’ 1835-40 ‘Mammif.,’ s.
39 pl. xiv. There is a specimen of this fine animal in the British
Museum.
[53] Even Pallas admits this; _see_ ‘Act. Acad. St. Petersburgh,’
1780, p. 93.
[54] Quoted by I. Geoffroy, ‘Hist. Nat. Gén.,’ tom. iii. p. 453.
[55] F. Cuvier in ‘Annales du Muséum,’ tom. xviii. p. 337; Godron ‘De
l’Espèce,’ tom. i. p. 342; and Col. H. Smith in ‘Nat. Library,’ vol.
ix. p. 101. _See also_ some observations on the degeneracy of the
skull in certain breeds, by Prof. Bianconi, ‘La Theorie Darwinienne,’
1874, p. 279.
[56] Dr. Burt Wilder, ‘American Assoc. Advancement of Science,’ 1873,
pp. 236, 239.
[57] Isid. Geoffroy Saint-Hilaire ‘Hist. des Anomalies,’ 1832, tom. i.
p. 660, Gervais ‘Hist. Nat. des Mammifères,’ tom. ii., 1855, p. 66. De
Blainville (‘Ostéographie, Canidæ,’ p. 137) has also seen an extra
molar on both sides.
[58] ‘Ostéographie, Canidæ,’ p. 137.
[59] Würzburger ‘Medecin. Zeitschrift,’ 1860, B. i. s. 265.
[60] Mr. Yarrell in ‘Proc. Zoolog. Soc.,’ Oct. 8th, 1833. Mr.
Waterhouse showed me a skull of one of these dogs, which had only a
single molar on each side and some imperfect incisors.
[61] Quoted in ‘The Veterinary,’ London, vol. viii. p. 415.
[62] This is quoted from Stonehenge, a great authority, ‘The Dog,’
1867, p. 187.
[63] ‘Hist. Nat. Général,’ tom. iii. p. 448.
[64] W. Scrope ‘Art of Deer-Stalking,’ p. 354.
[65] Quoted by Col. Ham. Smith in ‘Nat. Lib.,’ vol. x. p. 79.
[66] De Blainville ‘Ostéographie, Canidæ,’ p. 134. F. Cuvier ‘Annales
du Muséum,’ tom. xviii. p. 342. In regard to mastiffs, _see_ Col. H.
Smith ‘Nat. Lib.’ vol. x. p. 218. For the Thibet mastiff, _see_ Mr.
Hodgson in ‘Journal of As. Soc. of Bengal,’ vol. i., 1832, p. 342.
[67] ‘The Dog,’ 1845, p. 186. With respect to diseases Youatt asserts
(p. 167) that the Italian greyhound is “strongly subject” to polypi in
the matrix or vagina. The spaniel and pug (p. 182) are most liable to
bronchocele. The liability to distemper (p. 232) is extremely
different in different breeds. On the distemper, _see also_ Col.
Hutchinson on ‘Dog Breaking,’ 1850, p. 279.
[68] _See_ Youatt on the Dog, p. 15; ‘The Veterinary,’ London, vol.
xi. p. 235.
[69] ‘Journal of As. Soc. of Bengal,’ vol. iii. p. 19.
[70] ‘Travels,’ vol. ii. p. 15.
[71] Hodgson in ‘Journal of As. Soc. of Bengal,’ vol. i. p. 342.
[72] ‘Field Sports of the North of Europe,’ vol. ii. p. 165.
[73] ‘Hist. Nat. des Mammif.,’ 1855, tom. ii. pp. 66, 67.
[74] ‘History of Quadrupeds,’ 1793, vol. i. p. 238.
[75] ‘Oriental Field Sports,’ quoted by Youatt, ‘The Dog,’ p. 15.
[76] A. Murray gives this passage in his ‘Geographical Distribution of
Mammals,’ 4to, 1866, p. 8.
[77] Quoted by Mr. Galton, ‘Domestication of Animals,’ p. 13.
[78] ‘Hist. Nat. Gén.,’ tom. iii. p. 450.
[79] Mr. Greenhow on the Canadian Dog in Loudon’s ‘Mag. of Nat.
Hist.,’ vol. vi., 1833, p. 511.
[80] _See_ Mr. C. O. Groom-Napier on the webbing of the hind feet of
Otterhounds in ‘Land and Water,’ Oct. 13, 1866, p. 270.
[81] ‘Fauna Boreali-Americana,’ 1829, p. 62.
[82] ‘The Horse in all his Varieties,’ etc., 1829, pp. 230, 234.
[83] ‘The Dog,’ 1845, pp. 31, 35; with respect to King Charles’s
spaniel, p. 45; for the setter, p. 90.
[84] In the ‘Encyclop. of Rural Sports,’ p. 557.
[85] Author of ‘Researches into the History of the British Dog.’
[86] _See_ Col. Hamilton Smith on the antiquity of the Pointer, in
‘Nat. Lib.’ vol. x. p. 196.
[87] The Newfoundland dog is believed to have originated from a cross
between the Esquimaux dog and a large French hound. _See_ Dr. Hodgkin
‘British Assoc.,’ 1844; Bechstein ‘Naturgesch. Deutschland,’ B. i. s.
574; ‘Nat. Lib.,’ vol. x. p. 132; also Mr. Jukes’ ‘Excursion in and
about Newfoundland.’
[88] De Blainville ‘Ostéographie, Felis,’ p. 65, on the character of
_F. caligulata_; pp. 85, 89, 90, 175, on the other mummied species. He
quotes Ehrenberg on _F. maniculata_ being mummied.
[89] Asiatic Soc. of Calcutta; Curator’s Report, Aug. 1856. The
passage from Sir W. Jardine is quoted from this Report. Mr. Blyth, who
has especially attended to the wild and domestic cats of India, has
given in this Report a very interesting discussion on their origin.
[90] ‘Fauna Hungariæ Sup.,’ 1862, s. 12.
[91] Isid. Geoffroy Saint-Hilaire, ‘Hist. Nat. Gén.,’ tom. iii. p.
177.
[92] ‘Proc. Zoolog. Soc.,’ 1863, p. 184.
[93] ‘Säugethiere von Paraguay,’ 1830, s. 212.
[94] ‘Mem. présentés par divers Savans: Acad. Roy. des Sciences,’ tom.
vi. p. 346. Gomara first noticed this fact in 1554.
[95] ‘Narrative of Voyages,’ vol. ii. p. 180.
[96] J. Crawfurd ‘Descript. Dict. of the Indian Islands,’ p. 255. The
Madagascar cat is said to have a twisted tail; _see_ Desmarest in
‘Encyclop. Nat. Mamm.,’ 1820, p. 233, for some of the other breeds.
[97] Admiral Lutké’s Voyage, vol. iii. p. 308.
[98] ‘Zoology of the Voyage of the Beagle, Mammalia,’ p. 20.
Dieffenbach ‘Travels in New Zealand,’ vol. ii. p. 185. Ch. St. John
‘Wild Sports of the Highlands,’ 1846, p. 40.
[99] Quoted by Isid. Geoffroy ‘Hist. Nat. Gén.,’ tom. iii. p. 427.