prehistoric European horse, it is now convenient to speak of as the
Southern or Arabian horse. There are certain curious structural features
which seem to mark these horses and their offspring, even when their
strain is blended with that of the more Northern horse. Probably from
the time of the cave-men onward the selective breeding of horses has
been carried on, so that in many breeds size has been vastly increased.
It is an important fact that the English racehorse has never been
selected and bred for “points” (as cattle and sheep are), but always by
performance on the racecourse. Thus it becomes an extremely interesting
matter to see what are the changes which the breeder of thoroughbred
stock has unconsciously produced—what are the differences between the
racehorse of to-day and that of 50, 100, and 150 years ago. This was
pointed out to me by the late Duke of Devonshire as a reason for
supporting my proposal to secure and place in the Natural History Museum
the skulls, limb-bones, hoofs, and other indestructible parts of great
racehorses (and of other breeds), and also for having very accurately
measured reduced models made of such horses, in order that we may after
some years compare the proportions and structure at present arrived at
with the later developments which the continual selection of winner’s
blood in breeding must unconsciously produce. Such a collection was
started by me in the museum, but it needs the assistance of owners of
horses—both as to placing record specimens in the museum and in paying
for the preparation of accurately reduced models by competent artists.
It already comprises the skulls of Stockwell, Bend Or, and Ormonde, and
several carefully made reduced models of celebrated horses. There is no
doubt that the English racehorse has increased in size. He is a bigger
animal to-day than he was 200 years ago, and the opinion of the best
authorities is that he has increased on the average an inch in height at
the withers in every twenty-five years. The racehorse has a much longer
thigh-bone and upper-arm bone (in proportion to the rest of the leg)
than has the cart-horse, and it is probable that this length has been
continually increased by the selection of winners for breeding.
There are other points of scientific interest as to modern horses and
their forefathers which are illustrated by valuable specimens and
preparations placed by me in the Natural History Museum.
All those hairy warm-blooded quadrupeds which suckle their young, and
are hence called mammals, are the descendants of small five-toed
ancestors about the size of a spaniel. This is equally true of the
elephant, the gorilla, the horse, and the ox. In the sands and clays
deposited since the time of the chalk-sea, the remains (bones and teeth)
of the ancestors of living mammals are found in great abundance. These
sands and clays are called “the Tertiaries,” and are divided into lower,
middle, and upper—whilst we recognise as “Post-Tertiaries” (or
Quaternary) the later formed gravel and cave deposits in which the
remains and weapons of the cave-men have been found. The Tertiaries
consist of a series of deposits amounting to about 3000 feet in
thickness, and they have taken several million years in depositing—no
one can say how many.
[Illustration: HIPPARION HORSE
FIG. 10.—To the left, the fore-foot of the horse-ancestor, Hipparion,
showing three toes: to the right, the back view of a long bone of a
modern horse’s foot, with rudiments of outer toes, called splint-bones.]
In the upper Tertiary we find the remains of a kind of horse (the
Hipparion), with well-developed “petti-toes” (like those of a pig) on
each side of the big central toe (Fig. 10). In the middle Tertiary we
find smaller ancestral horses, with three toes of nearly equal size, and
in the lower Tertiary a horse-ancestor as small as a fox-hound (the
Hyracotherium), with four toes on its front foot and three on its hind
foot. Coming very close to this in general character is another small
extinct animal of the same age, with five toes on each foot. As the toes
have dwindled in number and size, leaving at last only the big central
toe (as we pass upward from the small ancestors to the big modern
horse), so the cheek-teeth, too, have changed. At first they had shallow
crowns and divided fangs, and showed four prominences on the crown which
were little, if at all, worn down during life. But as the horse became a
bigger animal and took to eating coarse tooth-wearing grass, his teeth
became deeper, and continued to grow for a long time, whilst the crown
was rubbed down by the hard food, and a curiously complex pattern was
brought into view by the exposure of the irregular bosses of the crown
in cross section. And, meanwhile, the size and proportions of the
horse-ancestors changed until, after being pig-like, then tapir-like,
they acquired the perfect form and size for fleet and prolonged movement
over firm, grass-grown plains. Horses and other large animals have to
run, not only to escape pursuit by carnivorous enemies, but in order to
travel, before they die from thirst, from a region suddenly dried up by
drought to a region where water can be had. Many thousands of wild
animals perish every year from local droughts in Africa. No small
animals can exist in regions liable to be affected by sudden drought.
Three-toed horses, like the upper Tertiary Hipparion, are occasionally
born as “monstrosities” from ordinary horses at the present day. All
horses have the remnant of a toe on each side of the big central toe—in
the form of splint-bones—concealed beneath the skin. In some breeds,
for instance, in the “Shire” horses, which have enormous hairy feet in
proportion to their huge strength and weight, these splint-bones tend to
develop three little toe-joints, which are immovable, but obviously are
“petti-toes.” It is related by Suetonius that Julius Cæsar used to ride
a favourite horse which had several toes on each foot with claws like a
lion. This was one of the “monstrosities” alluded to above, a throw-back
to the ancestral many-toed condition. Specimens illustrating these, and
all else which I am here relating concerning horses, and much more which
I have not space to tell, may be seen in the North Hall of the Natural
History Museum.
[Illustration: FIG. 11.—Skulls of horses and of deer to show the
pre-orbital pit or cups _pf_, and its absence in the Mongolian
(Prevalsky’s) horse.]
The three-toed ancestral horse, Hipparion, attained a fair size (that of
a big donkey), and was shaped like the recent fleet one-toed horses. In
the skull in front of the orbit, the Hipparion has a strongly marked
depression in the bone, as long and broad as a hen’s egg, and in shape
like one-half of an egg cut through longwise (see Fig. 11 _pf_). These
pre-orbital cavities are known in deer, sheep, and antelopes; they lodge
a gland resembling the tear-gland, which has, itself, a separate
existence. Similar “glands” are found in the feet and ankle-joints of
sheep and deer. The fluid which they secrete probably has an odour (not
readily noticed by man) which helps to keep the herd together, or, on
certain tracks when the fluid is smeared on to herbage. It is a
remarkable fact that the skulls of the wild Mongolian horse and of the
fossil horse of the cave-men, as also those of the commoner European
breeds, have no trace of this pre-orbital cup or of the gland which
Hipparion, their three-toed ancestor, possessed. Nor, indeed, have the
asses and zebras. But the Southern horse, the Arab, and all the breeds
into which his blood has prominently entered—as, for instance, the
English racer (so-called “thoroughbred”) and the “Shire” horse (which
is derived from the old English war-horse, in the making of which
certainly four hundred years ago Arab blood and heavy Northern stock
were mingled), do show, as a rule, a well-marked if shallow, cup-like
depression in front of the orbit! In fact, as Mr. Lydekker has pointed
out, the presence of this “pre-orbital cup” is evidence of the descent
of its possessor from Arab ancestry. Many specimens of horses’ skulls
showing this “cup” are exhibited in the Natural History Museum. We have
not been able to find any trace of a gland like the “larmier” of deer
and the “crumen” of antelopes on examining the soft tissues which
overlie this cavity in horses of Arab descent, but it is not improbable
that occasional instances of such survival will some day come to light.
A very interesting fact in connection with this concavity and its
indication of a distinction between the Northern (Mongolian) and the
Southern (Arabian) horse is that in India a fossil horse of very late
Tertiary date has been found, a true one-toed horse, not a Hipparion,
which has the pre-orbital cup well marked, and is possibly the ancestor
of the Arab.
There is no very great difference between the wild horse and wild asses
and zebras. They are distinct “species,” but will breed together and
produce “mules,” which in rare cases appear to be themselves fertile,
although this is doubtful. The inner causes of the infertility of mules
are not really known or understood. Nor, in fact, do we know really and
experimentally what are the causes of fecundity and of infecundity in
normally paired animals, including mankind. It is of the utmost
importance to modern Statecraft that this subject should be studied, and
there is a great field for experimental inquiry.
A clear mark of difference between the horse and the other species of
the genus Equus (namely, the Asiatic and African asses and the zebras)
is found in the curious wart-like knobs[1] on the legs, which are called
“chestnuts.” These warty knobs appear to be the remains in a “dried up”
condition of glands, such as are found in the legs of deer in a similar
position, and secrete a glairy fluid. In new-born colts they sometimes
exude a fluid, and also more rarely in adult horses. The fluid attracts
other horses (probably by its smell), and also causes dogs to keep
quiet. The horse has one of these wart-like “chestnuts” above the wrist
joint (so-called knee) on the inner side of the fore-leg. And so have
all the asses and zebras. But the horse (Fig. 12) has also a similar
“chestnut” on the inner side of each of its hind-legs, below the
heel-bone, or “hock.” This hind-leg chestnut is absent in all asses and
zebras. This difference between the horse and ass can be tested by my
readers on any roadside by their own observation. The hind-leg chestnut
is also absent in certain breeds of ponies from Iceland and the
Hebrides. Its presence and absence are interesting in connection with
the disappearance of the face-gland or pre-orbital gland in all recent
horses, asses, and zebras.
[Illustration: FIG. 12.—Fore and hind legs of horse and ass, to show
the “chestnuts,” and the absence of that structure from the hind-leg of
the ass.]
The “chestnuts” of the horse have sometimes been compared erroneously to
the “pads” on the feet of other animals, and supposed to be survivals of
a “pad” in each foot corresponding to the inner of the three toes of
the Hipparion. The real representative, in the horse, of the chief pad
of the foot of animals which do not (as the horse does) walk on the very
tip of the toe, is a little knob called the “ergot.” The diagram, Fig.
13, shows how this ergot corresponds to the chief pad of the three-toed
tapir’s foot, and so to that of the dog also.
[Illustration: FIG. 13.—Diagram of the under surface of the foot in the
dog, tapir, and horse, to show that the horny knob of the horse’s foot,
called the “ergot,” corresponds to the central “pad” of the other two.]
The absence of living horses, or of any kind of ass or zebra, from the
American Continent, when first colonised by Europeans in the sixteenth
century, is a very singular fact. For we find a great number and variety
of fossil remains of extinct horses in both North and South America. It
seems possible that some epidemic disease swept them from the whole
Continent not very many centuries before Europeans arrived—for there is
evidence in South America of the co-existence there of peculiar kinds of
horse with the “Indian” natives. It is even alleged that Cabot, in 1530,
saw horses in Argentina, which were the last survivors of the native
South American species. And it is also said that the Araucanian Indians
of Patagonia have a peculiar breed of ponies, which may be derived in
part from a native South American stock. I have never been able to
procure a skull of this breed, or any detailed description of it. What
is quite certain is that in the great cave of Ultima Speranza, in
Patagonia—from which the hairy skin, dried flesh and blood, and
unaltered dung as well as the bones, of the giant sloth Mylodon were
obtained—a great number of the horny hoofs, and the teeth of a peculiar
horse were also found some eight years ago, and are preserved in the
Natural History Museum, together with the remains of the giant sloth.
The condition of these remains is such that they cannot be many
centuries old. The animals appear to have been contemporaneous with an
early race of Indians who made use of the cave before the arrival of
Europeans. A skull of one and a skeleton of another of the peculiar
extinct South American horses (called Onohippidium and Hippidium), which
survived until a late period in Patagonia and may possibly have been
seen by Cabot, are shown in the Natural History Museum. Their bones are
found in the superficial gravel and sand of the pampas.
To revert for a moment to the history of the English thoroughbred. It
appears that in England in the middle of the eighteenth century a happy
new infusion of the Arab race with that of existing stock (which already
contained some Arab blood mixed with that of the Northern race) produced
once and for all a very perfect and successful breed. That breed did not
derive speed from the Arab, but “stamina,”—probably a powerful heart.
It did not derive its size from the Arab, but the cross proved to be a
large horse. It has never been improved since by any further admixture
of Arab or Southern blood. Hence the (at first sight) misleading name
“thoroughbred.” This name is not intended to imply that the breed is not
originally a “blend,” but that those horses so called are pure-bred from
the happy and wonderful mixture which a hundred and fifty years ago was
embodied in the great sires Matchem, Herod, and Eclipse.
FOOTNOTES
[1] The names “malander” and “salander” have been recently applied by
zoological writers, apparently by misconception, to these “callosities”
or “chestnuts.” Those names are used by veterinary surgeons to describe
a diseased condition of this part of the horse’s leg (Italian “_mal
andare_”), and do not apply to the “chestnut” itself, which is sometimes
called “castor.”
XI
A RIVAL OF THE FABLED UPAS TREE
We are so accustomed nowadays to danger to life and health from minute,
invisible germs, and to exerting all our skill in order to destroy them,
that the knowledge of the existence of large and beautiful trees in our
midst which can, and do, cause terrible disease and suffering by their
mere presence, comes as a shock, and produces a peculiar sense of
insecurity greater even than that excited by unseen micro-organisms. For
the trees of which I am about to speak are cultivated in our gardens,
trained up against the walls of our houses with loving care, and admired
for the beautiful autumn tints of their leaves. Yet it is now certain
that they are the cause in many persons of most terrible suffering and
illness. I am glad to be able to warn my readers in regard to these
plants, and I shall be very much interested to hear whether the
information which I am about to give proves to be of value in any
particular case.
A married couple, friends of my own, went to live, about fourteen years
ago, in a newly built, detached house, standing in its own garden, in
the neighbourhood of an English city. After they had been there two
years the lady developed a very painful eruption or eczema on the face,
which, in the course of a few weeks, caused the eyes, nose, and lips to
swell to an extraordinary degree, accompanied by the formation of
blisters and breaking of the skin. The affection spread to the body, and
caused constant pain and corresponding prostration. Her medical
attendants were unable either to cure or to account for her condition.
After some months she left home, and entirely recovered. But every year
the same distressing and disfiguring illness attacked her (commencing in
the month of June), and disappeared as soon as she left her house, only
to return when she came back to it. The doctors spoke of her affliction
as a mysterious form of erysipelas, and even suggested blood-poisoning
as the cause. For long periods she was so ill and in so much pain that
she was unable to see her friends, and her life was at times in danger.
Two years ago a weekly newspaper published an account, written by a
correspondent, of an illness from which he had suffered—exactly
agreeing with that which had for so many years tortured my friend’s
wife. This writer stated that he had ascertained that the disease was
due to the action of a poison given off by a creeper which grew on the
walls of his house. He had supposed this plant to be a Virginian
creeper; but he had discovered that it was in reality the Californian
poison-vine called by botanists _Rhus toxicodendron_. The terribly
poisonous nature of this plant is well-known to the people of the United
States. It is one of the sumach trees, of which other poisonous kinds
are known, whilst more than one species is used (especially in Japan)
for preparing a resinous varnish which is used in the manufacture of
“lacquered” articles. The writer in the weekly paper stated that he had
cut down and burnt the poison-vine which grew on the walls of his house,
and that his sufferings had ceased. My friend happened to read this
account, and immediately examined his own house. He found a creeper
resembling a Virginian creeper, but having three leaflets or divisions
of the leaf instead of five, growing around his drawing-room window, and
actually spreading its branches and leaves over the window of his wife’s
bedroom. He sent specimens of the creeper to Kew, where it was at once
identified as the _Rhus toxicodendron_ or American poison-vine or
poison-ivy. He caused the plant to be removed and burnt, and, except for
a slight attack in July, due no doubt to fragments of the leaves still
carried about in the form of dust, his wife has recovered her health.
I have looked into this matter with care, and I find that (presumably in
ignorance) nurserymen in England have sold specimens of the poison-vine
for planting as creepers, under the name _Ampelopsis Hoggii_. The
smaller-leaved Virginian creeper, with self-attaching tendrils, is known
as _Ampelopsis Veitchii_, and is, like the larger Virginian creeper (_A.
quinquefoliata_), quite harmless. The poison-vine is not an Ampelopsis
at all, not even one of the Vitaceæ or vine family, as that genus is. It
is a Sumach or Rhus, and belongs to a distinct family, the
Terebinthaceæ. It has a three-split leaf, not five leaflets, as has the
large Virginian creeper, nor a small three-pointed leaf, as has the
_Ampelopsis Veitchii_. The _Veitchii_ frequently has the leaf also split
into three leaflets, but the stalk of the middle leaflet is not
relatively so long as it is in the poison-vine. The differences and
resemblances in the leaves of these plants are shown in the accompanying
illustration (Fig. 14), which has been prepared from actual specimens
for this book.
The people of the United States are on their guard against this plant,
knowing its terrible properties. Sir William Thiselton Dyer, formerly
director of Kew Gardens, tells me that specimens of the “American
poison-vine” are grown in the garden at Kew, and that he has been
present when American visitors (ladies) literally screamed with horror
on seeing it, and ran from it as from a mad dog. Several cases are on
record of the mysterious poisoning produced by this plant in England;
but it is strangely unfamiliar to medical practitioners—indeed,
practically unknown to them, although I have ascertained that many
English people, especially ladies, have been victims for some years to
its unsuspected influence.
At the University of Harvard, in Cambridge, Massachusetts, they have
made quite recently a thorough examination of the poison-vine in the
laboratory, with the following results: The poison is an oil—a fixed
oil, not a volatile one, as we might have imagined from its mysterious
action at a distance. The oil exists in all parts of the plant, even in
the fine hairs and cuticle of the leaf. It can be extracted by means of
ether, and is one of the most virulent irritants known, having a very
curious penetrating and persistent action, and producing violent pain
and destruction of tissue when placed on the skin in quantity so minute
(one-thousandth of a milligram in two drops of olive oil) as to be
beyond the terms of everyday language. It seems to be usually brought to
the eyes, nose, lips, and skin of the face and body by the fingers which
have touched a leaf or fragments of a leaf in powder. The dead leaf in
winter still retains the oil, and minute dust-like particles can carry
it. The treatment for it is washing with soap, oil, and ether at an
early stage of the attack—especial care being taken to free the fingers
from any minute traces of the oil adhering to them.
[Illustration: FIG. 14.—Drawings, about half the natural size, of the
leaves of the common quinquefoliate Virginian creeper (1 and 2), of the
adherent “Ampelopsis Veitchii” (3 and 4), and of the poison-vine, _Rhus
toxicodendron_ (5 and 6). From specimens in the Botanical Department of
the Natural History Museum. Note especially the greater length of the
stalk of the central leaflet in the poison-vine. Note also that the
common Virginian creeper has sometimes only three leaflets (2) instead
of five, and that “Veitchii” has either three leaflets, as in 3, or has
the leaflets united into one three-pointed leaf, as in 4.]
The poison of the poison-vine only acts upon a limited number of
individuals, many people being perfectly immune. At the same time, the
effect upon susceptible people appears to be enhanced with every fresh
attack; even after the total removal of the poison-vine and its dust
from proximity to a susceptible person, he or she is apt for some
time—owing to the retention of some trace of the oil in the skin or
clothes—to have slight attacks. According to a writer who two years ago
gave in the _Spectator_ an account of his own case, the first symptom of
an attack is almost invariably a redness and irritation of the eyelids,
accompanied by shivering. In a few hours the eyelids are closed, the
features unrecognisable, and the skin covered with little blisters. Then
the lips swell enormously, the glands of the neck also. In four days the
arms and hands are reached, each finger appearing as if terribly scalded
and requiring separate bandaging. Then sometimes the lower limbs are
involved. After ten days the attack passes off, leaving the patient in a
pitiable state of weakness to grow a new skin and recover from other
painful results of the poisoning. But no immunity is conferred by an
attack; the unhappy victim (who is ignorant of the cause of his
sufferings) may, and frequently does, get a new dose of the poison as
soon as he has recovered, and the whole course of the illness has again
to be passed through. If this account should fall into the hands of any
one who is being unwittingly poisoned by the American poison-vine, and
may therefore be saved by what I have written from further suffering, I
shall be greatly pleased.