RELATIVE INFLUENCE OF THE PARENTS.
The relative influence of the male and female parents upon the
characteristics of progeny has long been a fertile subject of
discussion among breeders. It is found in experience that progeny
sometimes resembles one parent more than the other,--sometimes there
is an apparent blending of the characteristics of both,--sometimes a
noticeable dissimilarity to either, though always more or less
resemblance somewhere, and sometimes, the impress of one may be seen
upon a portion of the organization of the offspring and that of the
other parent upon another portion; yet we are not authorized from such
discrepancies to conclude that it is a matter of chance, for all of
nature's operations are conducted by fixed laws, whether we be able
fully to discover them or not. The same causes always produce the same
results. In this case, not less than in others there are, beyond all
doubt, fixed laws, and the varying results which we see are easily and
sufficiently accounted for by the existence of conditions or modifying
influences not fully patent to our observation.
In the year 1825, the Highland Society of Scotland, proposed as the
subject of prize essays, the solution of the question, "whether the
breed of live stock connected with agriculture be susceptible of the
greatest improvement from the qualities conspicuous in the male or
from those conspicuous in the female parent?" Four essays received
premiums. Mr. Boswell, one of the prize writers, maintained that it is
not only the male parent which is capable of most speedily improving
the breed of live stock, "but that the male is the parent which we can
alone look to for improvement."
His paper is of considerable length and ably written--abounding in
argument and illustrations not easily condensed so as to be given
here, and it is but justice to add that he also holds that "before the
breed of a country can be improved, much more must be looked to than
the answer to the question put by the Highland Society--such as
crossing, selection of both parents, attention to pedigree, and to the
food and care of offspring."
And of crossing, he says, "when I praise the advantage of crossing, I
would have it clearly understood that it is only to bring together
animals _not nearly related_ but always of _the same breed_; never
attempting to breed from a speed horse and a draught mare or vice
versa." Crossing of breeds "may do well enough for once, but will end
in vexation, if attempted to be prolonged into a line."
Mr. Christian, in his essay, supports the view, that the offspring
bears the greatest resemblance to that parent whether male or female,
which has exerted the greatest sway of generative influence in the
formation of the foetus, "that any hypothesis which would assign a
superiority, or set limits to the influence of either sex in the
product of generation is unsound and inadmissible," and he thus
concludes--"as therefore it is unsafe to trust to the qualities of any
individual animal, male or female, in improving stock, the best bred
and most perfect animals of both sexes should be selected and employed
in propagation; there being, in short, no other certain or equally
efficacious means of establishing or preserving an eligible breed."
Mr. Dallas, in his essay, starts with the idea that the seminal fluid
of the male invests the ovum, the formation of which he ascribes to
the female; and he supports the opinion, that where external
appearance is concerned, the influence of the male will be discovered;
but in what relates to internal qualities, the offspring will take
most from the female. He concludes thus:--"When color, quality of
fleece, or outward form is wanted, the male may be most depended on
for these; but when milk is the object, when disposition, hardiness,
and freedom from diseases of the viscera, and, in short, all internal
qualities that may be desired, then the female may be most relied on."
One of the most valuable of these papers was written by the Rev. Henry
Berry of Worcestershire, in which, after stating that the question
proposed is one full of difficulty and that the discovery of an
independent quality such as that alluded to, in either sex, would be
attended with beneficial results, he proceeds to show, that it is not
to sex, but to high blood, or in other words, to animals long and
successfully selected, and bred with a view to particular
qualifications, whether in the male or female parent, that the quality
is to be ascribed, which the Highland Society has been desirous to
assign correctly.
The origin of the prevalent opinion which assigns this power
principally to the male, he explains by giving the probable history of
the first efforts in improving stock. The greatest attention would
naturally be paid to the male, both on account of his more extended
services, and the more numerous produce of which he could become the
parent; in consequence of which sires would be well-bred before dams.
"The ideas entertained respecting the useful qualities of an animal
would be very similar and lead to the adoption of a general standard
of excellence, towards which it would be required that each male
should approximate; and thus there would exist among what may be
termed fashionable sires, a corresponding form and character different
from, and superior to, those of the general stock of the country. This
form and character would in most instances have been acquired by
_perseverance in breeding from animals which possessed the important
or fancied requisites_, and might therefore be said to be almost
_confirmed_ in such individuals. Under these circumstances, striking
results would doubtless follow the introduction of these sires to a
common stock; results which would lead superficial observers to
remark, that individual sires possessed properties as _males_, which
in fact were only assignable to them as _improved_ animals."
The opinion entertained by some, that the female possesses the power
generally ascribed to the male, he explains also by a reference to the
history of breeding: "It is well known to persons conversant with the
subject of improved breeding, that of late years numerous sales have
taken place of the entire stocks of celebrated breeders of sires, and
thus, the females, valuable for such a purpose, have passed into a
great number of hands. Such persons have sometimes introduced a cow so
acquired to a bull inferior in point of descent and general good
qualities, and the offspring is known, in many instances, to have
proved superior to the sire by virtue of the dam's excellence, and to
have caused a suspicion in the minds of persons not habituated to
compare causes with effects, that certain females also possess the
property in question."
The writer gives various instances illustrative of his views, in some
of which the male only, and in others the female only, was the
high-bred animal, in all of which the progeny bore a remarkable
resemblance to the well-bred parent. He says, that where both parents
are equally well bred, and of nearly equal individual excellence, it
is not probable that their progeny will give general proof of a
preponderating power in either parent to impress peculiar
characteristics upon the offspring;--yet in view of all the
information we have upon the subject, he recommends a resort to the
best males as the most simple and efficacious mode of improving such
stocks as require improvement, and the only proceeding by which stock
already good can be preserved in excellence.
Mon. Giron[17] expresses the opinion that the relative age and vigor
of the parents exercises very considerable influence, and states as
the results of his observation, that the offspring of an old male and
a young female resembles the father less than the mother in
proportion as the mother is more vigorous and the father more
decrepit, and that the reverse occurs with the offspring of an old
female and a young male.
Among the more recent theories or hypotheses which have been started
regarding the relative influence of the male and female parents, those
of Mr. Orton, presented in a paper read before the Farmers' Club at
Newcastle upon Tyne, on the Physiology of Breeding, and of Mr. Walker
in his work on Intermarriage, as they both arrived to a certain
extent, at substantially the same conclusions by independent
observations of their own and as these seem to agree most nearly with
the majority of observed facts, are deemed worthy of favorable
mention.
The conclusions of Mr. Orton, briefly stated,[18] are, that in the
progeny there is no casual or haphazard blending of the parts or
qualities of the two parents, but rather that organization is
transmitted by halves, or that each parent contributes to the
formation of certain structures, and to the development of certain
qualities. Advancing a step further, he maintains, that the male
parent chiefly determines the external characters, the general
appearance, in fact, the outward structure and locomotive powers of
the offspring, as the framework, or bones and muscles, more
particularly those of the limbs, the organs of sense and skin; while
the female parent chiefly determines the internal structures and the
general quality, mainly furnishing the vital organs, i.e., the heart,
lungs, glands and digestive organs, and giving tone and character to
the vital functions of secretion, nutrition and growth. "Not however
that the male is without influence on the internal organs and vital
functions, or the female without influence on the external organs and
locomotive powers of their offspring. The law holds only within
certain restrictions, and these form as it were a secondary law, one
of limitations, and scarcely less important to be understood than the
fundamental law itself."
Mr. Orton relies chiefly on the evidence presented by _hybrids_, the
progeny of distinct species, or by crosses between the most distinct
varieties embraced within a single species, to establish his law. The
examples adduced are chiefly from the former. The _mule_ is the
progeny of the male ass and the mare; the _hinny_ that of the horse
and the she ass. Both hybrids are the produce of the same set of
animals. They differ widely, however, in their respective
characters--the mule in all that relates to its external characters
having the distinctive features of the ass,--the hinny, in the same
respects having all the distinctive features of the horse; while in
all that relates to the internal organs and vital qualities, the mule
partakes of the character of the horse, and the hinny of those of the
ass. Mr. Orton says--"The mule, the produce of the male ass and mare,
is essentially a _modified ass_: the ears are those of an ass somewhat
shortened; the mane is that of the ass, erect; the tail is that of an
ass; the skin and color are those of an ass somewhat modified; the
legs are slender and the hoofs high, narrow and contracted, like those
of an ass. In fact, in all these respects it is an ass somewhat
modified. The body and barrel, however, of the mule are round and
full, in which it differs from the ass and resembles the mare.
The hinny, on the other hand, the produce of the stallion and she ass,
is essentially a _modified horse_. The ears are those of a horse
somewhat lengthened; the mane flowing; the tail bushy, like that of
the horse; the skin is finer, like that of the horse, and the color
varies also, like the horse; the legs are stronger and the hoofs broad
and expanded like those of the horse. In fact, in all these respects
it is a horse somewhat modified. The body and barrel, however, of the
hinny are flat and narrow, in which it differs from the horse and
resembles the she ass.
A very curious circumstance pertains to the voice of the mule and the
hinny. The mule _brays_, the hinny _neighs_. The why and wherefore of
this is a perfect mystery until we come to apply the knowledge
afforded us by the law before given. The male gives the locomotive
organs, and the muscles are amongst these; the muscles are the organs
which modulate the voice of the animal; the mule has the muscular
structure of its sire, and brays; the hinny has the muscular structure
of its sire, and neighs."
In connexion with these examples Mr. Orton refers to a special feature
seen equally in the two instances, and which seems at first sight, a
departure from the principle laid down by him. It is this, both
hybrids, the mule and the hinny take after the male parents in all
their external characters save one, which is _size_. In this respect
they both follow the female parents, the mule being in all respects a
larger and finer animal than its sire, the ass; the hinny being in all
respects a smaller and inferior animal to its sire, the horse, the
body and barrel of the mule being large and round, those of the hinny
being flat and narrow; both animals being in these particulars the
reverse of their respective sires, but both resembling their female
parents.
In explanation of this seeming exception is adduced a well known
principle in physiology, which is, that the whole bony framework is
moulded in adaptation to the softer structures immediately related to
it; the muscles covering it in the case of the limbs; and to the
viscera in that of the great cavities which it assists in forming.
Accordingly, in perfect accordance with the views above expressed, the
_general_ size and form which must be mainly that of the _trunk_, will
be determined by the size and character of the viscera of the chest
and abdomen, and will therefore accord with that of the female parents
by whom the viscera in question are chiefly furnished.
The foregoing are the most important of Mr. Orton's statements. He
gives, however, numerous additional illustrations from among beasts,
birds and fishes, of which we quote only the following:
"The mule and the hinny have been selected and placed first, because
they afford the most conclusive evidence and are the most familiar.
Equally conclusive, though perhaps less striking instances, may be
drawn from other sources. Thus, it has been observed that when the
Ancon or Otter sheep were allowed to breed with common ewes, the cross
is not a medium between the two breeds, but that the offspring retains
in a great measure the short and twisted legs of the sire."
Buffon made a cross between the male goat and the ewe; the resulting
hybrid in all the instances, which were many, were strongly
characteristic of the male parent, more particularly in the hair and
length of leg. Curious enough, the number of teats in some of the
cases corresponded with those of the goat.
A cross between the male wolf and a bitch illustrates the same law;
the offspring having a markedly wolfish aspect; skin, color, ears and
tail. On the other hand, a cross between the dog and female wolf
afforded animals much more dog-like in aspect--slouched ears and even
pied in color. If you look at the descriptions and illustrations of
these two hybrids, you will perceive at a glance that the doubt arises
to the mind in the case of the first, 'what genus of _wolf_ is this?'
whereas in the case of the second, 'what a curious _mongrel dog_!'
The views of Mr. Walker in his work on Intermarriage, before alluded
to, agree substantially with those of Mr. Orton, _so far as regards
crossing between different breeds_; but they cover a broader field of
observation and in some respects differ. Mr. Walker maintains that
when both parents are of the _same breed_ that _either parent may
transmit either half_ of the organization. That when they are of
_different varieties_ or breeds (and by parity of reasoning the same
should hold, strongly, when hybrids are produced by crossing different
_species_) and supposing also that both parents are of equal age and
vigor, that the _male_ gives the _back head and locomotive organs_ and
the _female_ the _face and_ nutritive organs--I quote his language:
"when both parents are of the same variety, _one parent communicates
the anterior part of the head, the bony part of the face, the forms of
the organs of sense_ (the external ear, under lip, lower part of the
nose and eye brows being often modified) _and the whole of the
internal nutritive system_, (the contents of the trunk or the thoracic
and abdominal viscera, and consequently the form of the trunk itself
in so far as that depends on its contents.)
The resemblance to that parent is consequently found in the forehead
and bony parts of the face, as the orbits, cheek bones, jaws, chin and
teeth, as well as the shape of the organs of sense and the tone of the
voice.
_The other parent communicates the posterior part of the head, the
cerebel situated within the skull immediately above its junction with
the back of the neck, and the whole of the locomotive system_; (the
bones, ligaments and muscles or fleshy parts.)
The resemblance to that parent is consequently found in the back head,
the few more movable parts of the face, as the external ear, under
lip, lower part of the nose, eyebrows, and the external forms of the
body, in so far as they depend on the muscles as well as the form of
the limbs, even to the fingers, toes and nails. * *
It is a fact established by my observations that in animals of the
_same variety, either the male or the female parent_ may give _either
series of organs_ as above arranged--that is _either_ forehead and
organs of sense, together with the vital and nutritive organs, _or_
back head, together with the locomotive organs."
To show that among domesticated animals organization is transmitted by
halves in the way indicated, and that either parent may give either
series of organs, he cites among other instances the account of the
Ancon sheep. "When both parents are of the Ancon or Otter breed, their
descendants inherit their peculiar appearance and proportions of form.
When an Ancon ewe is impregnated by a common ram, the progeny
resembles wholly either the ewe or the ram. The progeny of a common
ewe impregnated by an Ancon ram follows entirely in shape the one or
the other without blending any of the distinguishing and essential
peculiarities of both.
'Frequent instances have occurred where common ewes have had twins by
Ancon rams; when one exhibited the complete marks and features of the
ewe and the other of the ram. The contrast has been rendered
singularly striking when one short legged and one long legged lamb
produced at a birth have been sucking the dam at the same time.'
As the short and crooked legs or those of opposite form, here indicate
the parent giving the locomotive system, it is evident that one of
the twins derived it from one parent and the other twin from the other
parent;--the parent not giving it, doubtless communicating in each
case, the vital or nutritive system."
Where the parents are of different varieties or species, Mr. Walker
says, "The second law, namely, that of CROSSING, operates where each
parent is of a _different breed_, and where, supposing both to be of
equal age and vigor the _male_ gives the _back head_ and _locomotive
organs_, and the _female_ the _face_ and _nutritive organs_."
After giving numerous illustrations from facts and many quotations
from eminent breeders, he says, "thus, in crosses of cattle as well as
of horses, the male, except where feebler or of inferior voluntary and
locomotive power, gives the locomotive system, the female the vital
one."
W.C. Spooner, V.S., one of the most eminent authorities of the present
day on this subject, and writing within the past year in the Journal
of the Royal Agricultural Society, says:--"The most probable
supposition is, that propagation is done by halves, each parent giving
to the offspring the shape of one half of the body. Thus the back,
loins, hind-quarters, general shape, skin and size follow one parent;
and the fore-quarters, head, vital and nervous system, the other; and
we may go so far as to add, that the former in the great majority of
cases go with the male parent, and the latter with the female. A
corroboration of this fact is found in the common system of putting an
ordinary mare to a thorough-bred horse; not only does the head of the
offspring resemble the dam but the forelegs likewise, and thus it is
fortunately the case that the too-frequently faulty and tottering legs
of the sire are not reproduced in the foal, whilst the full thighs and
hind quarters which belong to the blood-horse are generally given to
the offspring. There is however a minority of cases in which the
opposite result obtains. That size is governed more by the male parent
there is no great difficulty in showing; familiar examples may be
found in the pony-mare and the full sized horse, which considerably
exceed the dam in size. Again, in the first cross between the small
indigenous ewe and the large ram of another improved breed--the
offspring is found to approach in size and shape very much to the ram.
The mule offspring of the mare also much resembles both in size and
appearance its donkey sire. These are familiar examples of the
preponderating influence of the male parent, so far as the external
form is considered. To show however that size and hight do not
invariably follow the male, we need go no further for illustration
than the human subject. How often do we find that in the by no means
unfrequent case of the union of a tall man with a short woman, the
result in some instances is that all the children are tall and in
others all short; or sometimes that some are short and others tall.
Within our own knowledge in one case, where the father was tall and
the mother short, the children, six in number, are all tall. In
another instance, the father being short and the mother tall, the
children, seven in number, are all of lofty stature. In a third
instance, the mother being tall and the father short, the greater
portion of the family are short. Such facts as these are sufficient to
prove that hight or growth does not exclusively follow either the one
parent or the other. Although this is the case, it is also a striking
fact that the union of tall and short parents rarely, if ever,
produces offspring of a medium size--midway, as it were, between the
two parents.
Thus, in the breeding of animals, if the object be to modify certain
defects by using a male or female in which such defects may not exist,
we cannot produce this desired alteration; or rather it cannot be
equally produced in all the offspring, but can only be attained by
weeding out those in whom the objectionable points are repeated. We
are, however, of opinion that in the majority of instances, the hight
in the human subject, and the size and _contour_ in animals, is
influenced _much more by the male_ than the female parent--and on the
other hand, that the constitution, the chest and vital organs, and the
forehand generally more frequently follow the female."
Dr. Carpenter, the highest authority in Physiology, says "it has long
been a prevalent idea that certain parts of the organism of the
offspring" are derived from the male, and certain other parts from the
female parent; and although no universal rule can be laid down upon
this point, yet the independent observations which have been made by
numerous practical breeders of domestic animals seem to establish that
such a _tendency_ has a real existence; the characters of the _animal_
portion of the fabric being especially (but not exclusively) derived
from the male parent, and those of the _organic_ apparatus being in
like manner derived from the female parent. The former will be chiefly
manifested in the external appearance, in the general configuration of
the head and limbs, in the organs of the senses (including the skin)
and in the locomotive apparatus; whilst the latter show themselves in
the size of the body (which is primarily determined by the development
of the viscera contained in the trunk) and in the mode in "which the
vital functions are performed."
On the whole it may be said that the evidence both from observation
and the testimony of the best practical breeders goes to show that
each parent usually contributes certain portions of the organization
to the offspring, and that each has a modifying influence upon the
other. Facts also show that the same parent does not always contribute
the same portions, but that the order is reversed. Now, as no
operation of nature is by accident, but by virtue of _law_, there must
be fixed laws here, and there must also be, at times, certain
influences at work to modify the action of these laws. Where animals
are of distinct species, or of distinct breeds, transmission is
usually found to be in accordance with the rule above indicated, i.e.
the male gives mostly the outward form and locomotive system, and the
female chiefly the interior system, constitution, &c. Where the
parents are of the same breed, it appears that the portions
contributed by each are governed in large measure by the condition of
each in regard to age and vigor, or by virtue of individual potency or
superiority of physical endowment.
This _potency_ or power of transmission seems to be legitimately
connected with high breeding, or the concentration of fixed qualities
obtained by continued descent for many generations from such only as
possess in the highest degree the qualities desired. On the other hand
it must be admitted that there are exceptional cases not easily
accounted for upon any theory, and it seems not improbable that in
these the modifying influences may be such as to effect what may
approximate a reconstruction or new combination of the elements, in a
manner analogous to the chemical changes which we know take place in
the constituents of vegetables, as for instance, we find that sugar,
gum and starch, substances quite unlike in their appearance and uses,
are yet formed from the same elements and in nearly or precisely the
same proportions, by a chemistry which we have not yet fathomed.
Whether this supposition be correct or not, there is little doubt that
if we understood fully all the influences at work, and could estimate
fairly all the data to judge from, we might predict with confidence
what would be the characteristics of the progeny from any given union.
Practically, the knowledge obtained dictates in a most emphatic manner
that every stock-grower use his utmost endeavor to obtain the services
of the best sires; that is, _the best for the end and purposes in
view_--that he depend chiefly on the sire for outward form and
symmetry--that he select dams best calculated to develop the good
qualities of the male, depending chiefly upon these for freedom from
internal disease, for hardihood, constitution, and generally for all
qualities dependent upon the vital or nutritive system.
The neglect which is too common, and especially in breeding horses, to
the qualities of the dam, miserably old and inferior females being
often employed, cannot be too strongly censured. In rearing valuable
horses the dams are not of less consequence than the sires, although
their influence upon the progeny be not the same. This is well
understood and practiced upon by the Arab, who cultivates endurance
and bottom. If his mare be of the true Kochlani breed he will part
with her for no consideration whatever, while you can buy his stallion
at a comparatively moderate price. The prevalent practice in England
and America of cultivating speed in preference to other qualities, has
led us to attach greater importance to the male, and the too common
neglect of health, vigor, endurance and constitution in the mares has
in thousands of cases entailed the loss of qualities not less
valuable, and without which speed alone is of comparatively little
worth.
FOOTNOTES:
[17] In his work, "De la Generation," Paris, 1828.
[18] Quoted, in part, from a paper by Alex. Harvey, M.D., read before
the Medical Society of Southampton, June 6th, 1854.