Part 19

These experiments, however simple, have never yet been tried with a view to explain the nature of generation. I regret that it has not been in my power to try them, as I am persuaded consequences would result from them, which at present we only conjecture, and speak of as presumptions. I imagine, for example, that of all the above copulations, that of the great mule with the female bardeau, (the animal produced by the horse and ass) and that of the male-bardeau and she-mule might possibly not succeed: that the junction of the he and she-mule, and that of the male and female-bardeau, might sometimes be attended with success, though not often. That the he-mule would produce with the mare with greater certainty than with the she-ass, and the male-bardeau with more certainty with the she-ass than with the mare; and that the horse and he-ass might possibly produce with both the she-mules, but that the ass would be more successful than the horse. These experiments should be made in a country at least as warm as the south of France; and the age of the mules should be seven, the horses five, and the asses four years, because those different periods are necessary before those three animals acquire their full vigour.

These then are the analogical reasons on which the above presumptions are founded. In the common course of nature, it is not the males but the females which constitute the unity of species. We know from the example of the sheep, which propagate alike with the ram, or the goat, that the female has much more influence than the male, on the specific qualities of the production, since the only issue from these two different males are lambs, that is, individuals which have a specific resemblance to the mother. Thus the mule resembles the mare more than she does the ass, and the bardeau more the she-ass than the horse; therefore _the mule ought to produce more certainly with the mare than with the she-ass, and the bardeau still more so with the she-ass than with the mare, so the horse and he-ass might possibly produce with both the she-mules_; because being females, though somewhat vitiated, each retains more specific qualities than the male-mules; _but the he-ass should produce with them more certainly than the horse_; because it is observed, that the he-ass possesses stronger prolific powers than the horse, even with the mare, for the first corrupts and totally destroys the generation of the latter. We may be convinced of this fact by first taking a stallion to a mare, and the next morning, or even some days after, serving her with a male-ass, and her production will always be mules, and not horses. This fact, of which every circumstance deserves attention, seems to indicate, that the ass and not the horse, is the stock, or principal root of the family, since the first predominates by its prolific powers over the latter even with its own female, especially as, if the ass is first given to the mare and the horse afterwards, the latter does not destroy the generation of the former, for even then the production is still a mule. On the other hand, the like effect does not happen when the he-ass precedes the horse, with the she-ass, for the latter never destroys the operation of the former. With respect to the copulation of mules among themselves, I have presumed it to be sterile, for we can expect nothing else from two natures already debased by generation, and which by their union cannot fail of being still more debased, than a production entirely vitiated, or absolutely none at all.

By the mixture of the mule with the mare, of the bardeau with the she-ass, and the horse and he-ass with she mules, we should obtain individuals which would ascend towards the original species; they would be only half mules, and, like their parents, would not only have power to engender with their primitive species, but perhaps have the faculty of propagating among themselves; for being but half debased, their production would not be more vitiated than the first mules; and if the union of these half mules were sterile, or their productions rare, it appears almost certain, that by bringing them a degree still nearer their original species, the individuals which would result from such a union, and which would be no more than a fourth part debased, would produce among themselves and form a new stem, which would be precisely neither that of the horse nor the ass. Now as every thing possible has been accomplished in time, and either does exist, or has existed in Nature, I am inclined to think that the prolific mule spoken of by the ancients, and which in the days of Aristotle existed in Syria, beyond Phoenicia, might be a race of these half or quarter mules, which have been produced by the commixtures here spoken of: for Aristotle expressly says, that these prolific mules perfectly resembled the barren mules. He also very clearly distinguishes them from the onagres, or wild asses, which he mentions in the same chapter: consequently we can only refer these animals to mules which were but little vitiated, and preserved their reproductive faculties. The _czigithai_, or prolific mule of Tartary, of which we have before spoken, may also possibly not be the onagre, or the wild ass, but only this Phoenician mule, the race of which perhaps still remains. The first traveller who is able to compare them, will confirm or destroy this conjecture. The zebra itself, which even bears a greater resemblance to the horse than the ass, might probably have the same origin; the constrained regularity of his colours, alternately disposed in black and white stripes, seems to indicate that they proceed from two different species, which in their mixture have separated as much as possible; for Nature, in none of her works, is so abrupt, or so little shaded as on the coat of the zebra, where it suddenly and alternately changes from white to black, and from black to white, without any intermediate shade throughout the whole extent of the animal's body.

But however that may be, it is certain from what we have said, that mules in general, which have always been accused of sterility, are nevertheless neither really nor universally so; and that this sterility is only manifested in that particular kind of mule proceeding from the connection of the ass and the horse; for the mule produced by the he-goat and the ewe, is as prolific as its parents, and most mules which proceed from different species of birds, are not barren; therefore it is only in the particular nature of the horse and ass, that we must seek for the causes of the infecundity of the mules produced by them; and instead of supposing barrenness a general and necessary defect in every mule, it, on the contrary, should be limited to that mule alone which proceeds from the ass and the horse, and this limitation should be further restricted, as these mules prove prolific in certain circumstances, especially when brought a degree nearer their original species.

The mule, produced by the horse and the ass, has its organs of generation as complete as other animals; nothing seems wanting either in the male or female. The males have a great plenty of seminal liquor; and being never suffered to copulate, they are often so pressed for a discharge, that they frequently rest upon their bellies for that purpose. These animals are, therefore, provided with every thing necessary for the purpose of generation: they are even very ardent, and consequently, very indifferent in their choice. The males have nearly an equal vehement desire for the female mule, the she-ass, and the mare. There is, therefore, no difficulty in procuring the copulation, though it requires particular attention and care to render it prolific. A too strong ardour is often attended with sterility; and the female mule is at least as ardent as the she-ass. Now it is known that the latter rejects the seminal liquor of the male, and that to make her retain it, blows must be given, or cold water thrown over her crupper, to calm the convulsive emotions of desire which subsist after copulation, and which occasion this rejection. The she-ass, and the female mule, therefore, incline to sterility by their over-heat. The asses incline to it from another cause; for as they are originally natives of hot climates, cold opposes their generation, and this is the reason they are allowed to couple in summer only. If their union is permitted at any other time, and particularly in winter, it is seldom attended with impregnation. The season necessary to the success of their generation is as much so for the preservation of their production. If the young ass is not brought forth in warm weather it either languishes or dies; and as the time of the gestation with the ass is only once a year, she produces at the season she conceives: this sufficiently proves how necessary warmth is, not only for the fecundity but also for the life of these animals. This strong ardour of the female is the occasion of the male being given her almost immediately after she has brought forth, for she is seldom suffered to rest above seven or eight days between her delivery and copulation; weakened by the birth she is then less ardent, and from there not having been a sufficient interval allowed to strengthen the parts, the conception is more certain than when she is in full vigour. It is pretended, that in this species, as in that of the cat, the temperament of the female is more ardent than that of the male. However the he-ass is a great example of vigour, for he can cover females several times each day successively. He has been known to indulge his passions to so great an excess, as to die on the spot, after eleven or twelve reiterated efforts, almost without interval, and without refreshment, except a few draughts of water. This heat, which consumes the animal, is too strong to be lasting; the he-ass soon becomes unfit for service, and this, probably, is the reason of its being said the female is stronger and longer-lived than the male. It is certain, that with the proper care and management we have laid down, she will live thirty years, and bring forth every year of her life; whereas the male, when not kept from the females, abuses his strength to so great a degree as to lose the total power of engendering in a very few years.

The he and she-ass, therefore, both incline to sterility by common and also by different qualities. The horse and the mare have the same tendency. The mare may receive a stallion nine or ten days after she has brought forth, and she will produce five or six years successively, but after that time she becomes barren. To preserve her fecundity an interval of a year should be allowed between each birth, and instead of giving her the stallion immediately after she has foaled, she should be kept until she shews some external signs of heat. The mare seldom proves prolific after she is twenty years old; while the horse sometimes preserves the power of engendering until the age of thirty. The seminal liquor is less abundant, and less stimulating in the horse than in the ass; for the former often copulates without emitting, especially if the mare be presented to him before he seeks her. Besides, his most vigorous efforts are not always successful; for there are some mares naturally barren, and others whose fecundity is but trifling. There are also stallions which, though vigorous to all appearance, have but little power. To these particular reasons we can add a more evident and general proof of the small degree of fecundity there is in the horse and ass. Of all domestic animals, although they are the most carefully attended to, they are the least in number. In the ox, the sheep, the goat, and particularly the hog, dog, and cat, the individuals are ten, and, probably, a hundred times more numerous than those of the horse and ass. Thus their want of fecundity is proved by facts, and we must attribute the sterility of the mules to all the above causes, as they proceed from a mixture of these naturally unprolific species. In those species, on the contrary, which, like the sheep and goat, are numerous, and, consequently prolific, the mules proceeding from their intermixture, are not barren but ascend to the original species in the first generation, whereas, two, three, or perhaps four generations, are required to reinstate the mule produced by the horse and the ass, to the same degree and perfection of nature.

It has been asserted, that another kind of mule is produced from the copulation of the bull with the mare. Columella is, I think, the first who has spoken of it. Gesner quotes the words of Columella, and adds, that he found these mules in Grenoble, and which are called in French _jumars_. One of these jumars I had brought to me from Dauphiny, and another from the Pyrenees. By the inspection of the external parts, as well as by the dissection of the internal, I discovered that they were only bardeaus, or mules produced between the horse and the she-ass. I think myself, therefore, authorized from this experiment, and from analogy, to suppose this kind of mule does not exist, and that the word jumar is only a chimerical name without any real object. The nature of the bull is too distant from that of the mare, to admit of their engendering together, the one having four stomachs, horns, cloven feet, &c. and the other being whole-hoofed, with no horns, and only one stomach. The organs of generation are likewise so very different, there is not the least reason to suppose they can copulate with any degree of pleasure or success. If the bull were to produce with any species besides his own, it would be with the buffalo, which resembles him in conformation and natural habits; yet we have never heard of any mules being produced by the junction of these two animals. What is related of the copulation and production of the stag and cow, is nearly as suspicious as the story of the jumars, though the stag is much less distant, in its conformation, from the nature of the cow, than the bull is from that of the mare.

_END OF THE NINTH VOLUME._

Transcriber Note

All obvious typographical errors were corrected. Where several variant spellings were used, the most prevalent version was use to standardize them. All illustration headers were standardized to display "_Engraved for Barr's Buffon._" above each group and the captions were also standardized. The illustration captions were arranged in ascending numbers. Where paragraphs were split by illustrations, they were rejoined. To match the other volumes in this series, the list for the placement of images was positioned after the Table of Contents. Although the original printed version capitalized the first word (or words) of the opening paragraph, here the first letter only was capitalized (unless it was a person's name). Callitrix (for green monkey) should probably have been Callithrix which is a genus of New World monkeys whereas Callitrix is a genus of coniferous trees. This was left as printed.

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