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 a.s.s and the mare; the _hinny_ that of the horse and the she a.s.s. 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 a.s.s,--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 a.s.s. Mr. Orton says--"The mule, the produce of the male a.s.s and mare, is essentially a _modified a.s.s_: the ears are those of an a.s.s somewhat shortened; the mane is that of the a.s.s, erect; the tail is that of an a.s.s; the skin and color are those of an a.s.s somewhat modified; the legs are slender and the hoofs high, narrow and contracted, like those of an a.s.s. In fact, in all these respects it is an a.s.s somewhat modified. The body and barrel, however, of the mule are round and full, in which it differs from the a.s.s and resembles the mare.
The hinny, on the other hand, the produce of the stallion and she a.s.s, 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 a.s.s.
A very curious circ.u.mstance 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 a.s.s; 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 a.s.sists 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 ill.u.s.trations 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 b.i.t.c.h ill.u.s.trates 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 ill.u.s.trations 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 ill.u.s.trations 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 ill.u.s.tration 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 const.i.tution, 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, const.i.tution, &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 a.n.a.logous to the chemical changes which we know take place in the const.i.tuents 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, const.i.tution, 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 const.i.tution 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.
CHAPTER VI.
s.e.x.
With regard to the laws which regulate the s.e.x of progeny very little is known. Many and extensive observations have been made, but without arriving at any definite conclusions. Nature seems to have provided that the number of either s.e.x produced, shall be nearly equal, but by what means this result is attained, has not been discovered. Some physiologists think the s.e.x decided by the influence of the sire, others think it due to the mother. Sir Everard Home believed the _ovum_ or germ, previous to impregnation to be of no s.e.x, but so formed as to be equally fitted to become either male or female, and that it is the process of impregnation which marks the s.e.x and forms the generative organs; that before the fourth month the s.e.x cannot be said to be confirmed, and that it will prove male or female as the tendency to the paternal or maternal type may preponderate.
Mr. T.A. Knight[19] was of opinion that the s.e.x of progeny depended upon the influence of the female parent. He says, "The female parent"s influence upon the s.e.x of offspring in cows, and I have reason to believe in the females of our other domestic animals, is so strong, that it may, I think, be p.r.o.nounced nearly positive," He also says, "I have repeatedly proved that by dividing a herd of thirty cows into three equal parts, I could calculate with confidence upon a large majority of females from one part, of males from another, and upon nearly an equal number of males and females from the remainder. I have frequently endeavored to change the habits by changing the male without success." He relates a case as follows:--"Two cows brought all female offspring, one fourteen in fifteen years, and the other fifteen in sixteen years, though I annually changed the bull. Both however produced one male each, and that in the same year; and I confidently expected, when the one produced a male that the other would, as she did."
M. Giron, after long continued observation and experiment, stated with much confidence, that the general law upon this point was, that the s.e.x of progeny would depend on the greater or less relative vigor of the individuals coupled. In many experiments purposely made, he obtained from ewes more males than females by coupling very strong rams with ewes either too young, or too aged, or badly fed, and more females than males by a reverse choice in the ewes and rams he put together.
Mon. Martegoute, formerly Professor of Rural Economy, in a late communication to the "Journal D"Agriculture Pratique," says that as the result of daily observations at a sheepfold of great importance, that of the Dishley Mauchamp Merinos of M. Viallet at Blanc, he has, if not deceived, obtained some new hints. He states that Giron"s law developed itself regularly at the sheepfold in all cases where difference of vigor was observed in the ewes or rams which were coupled; but he adds another fact, which he had observed every year since 1853, when his observations began. This fact consists--
_First_, In that at the commencement of the rutting season when the ram is in his full vigor he procreated more males than females.
_Second_, When, some days after, and the ewes coming in heat in great numbers at once, the ram being weakened by a more frequent renewal of the exertion, the procreation of females took the lead.
_Third_, The period of excessive exertion having pa.s.sed, and the number of ewes in heat being diminished, the ram also found less weakened, the procreation of males in majority again commenced."
In order to show that the cause of such a result is isolated from all other influences of a nature to be confounded with it, he gives the details of his observations in a year when the number of births of males and females were about equal. He also goes on to say, that, "at the end of each month all the animals at the sheepfold are weighed separately, and thanks to these monthly weighings, we have drawn up several tables from which are seen the diminution or increase in weight of the different animals cla.s.sed in various points of view, whether according to age, s.e.x or the object for which they were intended.
Two of these tables have been appropriated to bearing ewes--one to those which have borne and nursed males and the other to those which have borne and brought up females. The abstract results of these two tables have furnished two remarkable facts.
_First_, The ewes that have produced the female lambs are, on an average, of a weight superior to those that produced the males; and they evidently lose more in weight than these last during the suckling period.
_Second_, The ewes that produce males weigh less, and do not lose in nursing so much as the others.
If the indications given by these facts come to be confirmed by experiments sufficiently repeated, two new laws will be placed by the side of that which Giron de Bazareingues has determined by his observations and experiments. On the one hand, as, at liberty, or in the savage state, it is a general rule that the predominance in acts of generation belongs to the strongest males to the exclusion of the weak, and as such a predominance is favorable to the procreation of the male s.e.x, it would follow that the number of males would tend to surpa.s.s incessantly that of the females, amongst whom no want of energy or power would turn aside from generation, and the species would find in it a fatal obstacle to its reproduction. But, on the other hand, if it was true that the strongest females and the best nurses amongst them produce females rather than males, nature would thus oppose a contrary law, which would establish the equilibrium, and by an admirable harmony would secure the perfection and preservation of the species, by confiding the reproduction of either s.e.x to the most perfect type of each respectively."
FOOTNOTES: