ON ANIMAL GENERATION. (continued 4)

EXERCISE THE THIRTIETH.

Of the uses of this disquisition on fecundity.

This disquisition on the inherent qualities of the egg and the cause of its fecundity, is alike in point of difficulty and subtlety, but of the highest importance. For it was imperative on us to inquire what there was in the conception, what in the semen masculinum, and what in the female fowl, which render these fertile; and what there is in the fruitful cock which makes him differ from a bird that is barren. Is the cause identical with that which we have called the vital principle (anima) in the embryo, or it is a certain portion of the vegetative principle? Because, in order to apprehend the entire cause of generation, it is of much moment that the first cause be understood; for science is based upon causes, especially first causes, known. Nor is this inquiry less important in enabling us to understand the nature of the vital principle (anima). These questions, indeed, rightly apprehended, not only are Aristotle’s opinions of the causes of generation refuted or corrected, but all that has been written against him is easily understood.

We ask, therefore, whether it is the same thing or something different, which in the rudimentary ovum, yelk, egg, cock and hen, or her uterus, confers fruitfulness? In like manner in what respect does this something agree or differ in each? Still farther, is it a substance whence the fecundating virtue flows?—it appears susceptible of powers, faculties, and accidents. Likewise, is it corporeal also? for that which engenders mixture appears to be mixed:—the progeny has a common resemblance to the mother and father, and exhibits a doubtful nature when animals of dissimilar species, such as the pheasant and common fowl, engender; that, too, appears to be corporeal which suffers from without, and to such an extent that not only are weakly embryos procreated, but even deformed and diseased ones, obnoxious to the vices as well as to the virtues of their progenitors.

With respect to these several particulars we may farther be permitted to doubt whether that which confers fecundity is engendered or accrues from without? Whether, to wit, it is transfused from the egg to the embryo and chick, from the hen to the egg, from the cock to the hen? For there appears to be something that is transferred or transfused, something, namely, which from the cock is transfused into the hen, and from her is given to the uterus, to the ovary, to the egg; something which passing from the seed to the plant, is rendered again by the plant to the seed, and imparts fecundity. Because there is this common to all things which are perpetuated by generation, that they derive their origin from seed. But the semen, the conception, and the egg, are all of the same essential kind, and that which confers fertility on these is one and the same, or of like nature; and this indeed is divine, the analogue of heaven, possessed of art, intelligence, foresight. This is plainly to be seen from its admirable operations, artifices, and wisdom, where nothing is vain, or inconsiderate, or accidental, but all conduces to some good end.

Of the general principles and science of this subject we shall treat more at length in the proper place; we have now said as much incidentally as seems necessary, the occasion having presented itself along with our consideration of the hen’s egg, namely, how many things inhere which induce fertility, and how this is induced, and whether it is an affection, a habit, a power, or a faculty; whether it is to be regarded as a form and substance, as a something contained generally, or only in some particular part—since it is quite certain that a hypenemic egg is a perfect egg in so far as each sensible particular is concerned, and yet is barren; the uterus in like manner, and the hen and the cock are all perfect; yet are they severally sterile, as being without that which confers fecundity. All of these matters we shall advert to after we have shown what and how two principles, male and female, concur in the production of the egg and the process of generation, and in what way both may be regarded as efficient causes and parents of the egg.

EXERCISE THE THIRTY-FIRST.

The egg is not produced by the cock and hen in the way Aristotle would have it.

It is certain, as we have said, that a fruitful egg is not produced without the concurrence of the cock and hen; but this is not done in the way that Aristotle thought, viz. by the cock as prime and sole ‘agent,’ the hen only furnishing the ‘matter.’ Neither do I agree with him when he says:[224] “When the semen masculinum enters the female uterus, it coagulates the purest portion of the catamenia;” and shortly afterwards: “but when the catamenia of the female has set in the uterus, it forms, with the semen masculinum, a coagulum like that of milk; for curd is milk containing vital heat, which attracts like particles around it, and combines and coagulates them; and the semen of the male (genitura) bears the same affinity to the nature of the catamenia. For milk and the menstrual discharge are of the same nature. When coagulation has taken place, then an earthy humour is excreted and is drawn around, and the earthy portion drying up, the membranes are produced both as matter of necessity, and also for a certain purpose. And these things take place in the same manner in all creatures, both oviparous and viviparous.”

But the business in the generation of an egg is very different from this; for neither does the semen, or rather the ‘geniture,’ proceeding from the male in the act of intercourse, enter the uterus in any way, nor has the hen, after she conceives, any particle of excrementitious matter, even of the purest kind, or any blood in her uterus which might be fashioned or perfected by the discharge of the male. Neither are the parts of the egg, the membranes, to wit, and the fluids, produced by any kind of coagulation; neither is there any thing like curdled milk to be discovered in the uterus, as must be obvious from the foregoing exercises. It follows, therefore, and from thence, that neither does the conception, whence the animal springs, as the herb arises from a fruitful seed, comport itself in the manner Aristotle imagined, since this takes place in viviparous animals in the same way as the egg is formed in oviparous animals, as he himself avows, and as shall be demonstrated by and by in our observations. Because it is certain that eggs of every description—prolific and barren—are engendered and formed by the hen singly, but that fecundity accrues from the male alone;—the cock, I say, contributes neither form nor matter to the egg, but that only by which it becomes fertile and fit to engender a chick. And this faculty the cock confers by his semen (genitura), emitted in the act of intercourse, not only on the egg that is already begun, or is already formed, but on the uterus and ovary, and even on the body of the fowl herself, in such wise that eggs which have yet to be produced, eggs, none of the matter of which yet exists either in the ovary or in any other part of the body, are thence produced possessed of fecundity.

EXERCISE THE THIRTY-SECOND.

Nor in the manner imagined by physicians.

Conception, according to the opinion of medical men, takes place in the following way: during intercourse the male and female dissolve in one voluptuous sensation, and eject their seminal fluids (genituræ) into the cavity of the uterus, where that which each contributes is mingled with that which the other supplies, the mixture having from both equally the faculty of action and the force of matter; and according to the predominance of this or of that geniture does the progeny turn out male or female. It is farther imagined that immediately after the intercourse, the active and passive principles cooperating, something of the conception is formed in the uterus. For contrary to the Aristotelians, they maintain that the male is no more the efficient cause of generation than the female, but some mixture of the two; and that neither the menstrual blood nor its purest part is the prime matter of the conception, but the spermatic fluid; whence the first particles or their rudiments are spoken of as spermatic, these at an after period being nourished and made to increase through the blood.

But it is obvious that neither is the egg engendered by the cock and hen in this way; for the hen in the act of intercourse emits no semen from which an egg might be formed; nor can aught like a seminal fluid of the hen be demonstrated at any time; and indeed the animal is destitute of the organs essential to its preparation, the testes and vasa spermatica. And though the hen have an effective force in common with the cock (as must be manifest from what precedes), and it is a mixture of some sort that renders an egg fruitful, still this does not happen according to the predominance of the genitures, or the manner of their mixture, for it is certain, and Fabricius admits it, that the semen of the cock does not reach the cavity of the uterus; neither is there any trace of the egg to be discovered in the uterus immediately after intercourse, and as its consequence, although Aristotle himself repeatedly avers that there is, asserting that “something of the conception forthwith ensues.” But I shall by and by demonstrate that neither does any such imaginary mixture of seminal fluids take place in any animal, nor that immediately upon intercourse, even of a fruitful kind, is there anything in the shape of semen or blood, or of the rudiments of an embryo present or demonstrable in the cavity of the uterus. Nothing is found in the egg or embryo which leads us to suppose that the semen masculinum is either there contained or mingled. The vulgar notion of the chalazæ being the tread of the cock is a sheer mistake; and I am surprised, since there are two of them, one in either end of the egg, that no one has yet been found to maintain that this was the cock’s seed, that the hen’s. But this popular error is at once answered by the fact that the chalazæ are present with the same characters in every egg, whether it be fertile or barren.

EXERCISE THE THIRTY-THIRD.

The male and the female are alike efficient in the business of generation.

The medical writers with propriety maintain, in opposition to the Aristotelians, that both sexes have the power of acting as efficient causes in the business of generation; inasmuch as the being engendered is a mixture of the two which engender: both form and likeness of body, and species are mixed, as we see in the hybrid between the partridge and common fowl. And it does indeed seem consonant with reason to hold that they are the efficient causes of conception whose mixture appears in the thing produced.

Aristotle entertaining this opinion says:[225] “In some animals it is manifest that such as the generator is, such is the engendered; not, however, the same and identical, not one numerically, but one specifically, as in natural things. A man engenders a man, if there be nothing preternatural in the way, as a horse [upon an ass] engenders a mule, and other similar instances. For the mule is common to the horse and the ass; it is not spoken of as an allied kind; yet may horse and ass both be there conjoined in a hybrid state.” He says farther in the same place: “It is enough that the generator generate, and prove the cause that the species be found in the matter: for such and such an entire species is still found associated with such and such flesh and bones—here it is Gallias, there it is Socrates.”

Wherefore if such an entire form, as a mule, be a mixture of two, viz.: a horse and an ass, the horse does not suffice to produce this form of a mule in the ‘matter;’ but, as the entire form is mixed, so another efficient cause is contributed by the ass and added to that supplied by the horse. That, therefore, which produces a mule compounded of two, must itself be an ‘adequate efficient,’ and mixed, if only ‘univocal.’ For example, this woman and that man engender this Socrates; not in so far as they are both human beings, and of one and the same species, but in so far as this man and that woman in these bones and muscles constitute human forms, of both of which, if Socrates be a certain mixture, a compound of both, that by which he is made must needs be a mixed univocal compound of the two; i. e. a mixed efficient of a mixed effect. And therefore it is that the male and female by themselves, and separately, are not genetic, but become so united in coitu, and made one animal as it were; whence, from the two as one, is produced and educed that which is the true efficient proximate cause of conception.

The medical writers also, in directing their attention to the particulars of human generation alone, come to conclusions on generation at large; and the spermatic fluid proceeding from the parents in coitu has in all probability been taken by them for true seed, analogous to the seeds of plants. It is not without reason, therefore, that they imagine the mixed efficient cause of the future offspring to be constituted by a mixture of the seminal matters of each parent. And then they go on to assert that the mixture proceeding immediately from intercourse is deposited in the uterus and forms the rudiments of the conception. That things are very different, however, is made manifest by our preceding history of the egg, which is a true conception.

EXERCISE THE THIRTY-FOURTH.

Of the matter of the egg, in opposition to the Aristotelians and the medical writers.

The position taken up by the medical writers against the Aristotelians, viz., that the blood is not the first element in a conception, is clearly shown from the generation of the egg to be well chosen: neither during intercourse, nor before nor after it, is there a drop of blood contained in the uterus of the fowl; neither are the rudiments of eggs red, but white. Many animals also conceive in whose uteri, if they be suddenly laid open after intercourse, no blood can be demonstrated.

But when they contend that the maternal blood is the food of the fœtus in utero, especially of its more sanguineous parts, as they style them, and that the fœtus from the outset is as it were a portion of the mother, being nourished and growing through her blood, and vegetating through her spirit; so that neither does the heart pulsate, nor the liver compose blood, nor any part of the fœtus perform any kind of independent office, but everything is carried on through the mother’s means, they in their turn are as certainly mistaken, and argue from erroneous observations. For the embryo in the egg boasts of its own blood, formed from the fluids contained within the egg; and its heart is seen to pulsate from the very beginning: it borrows nothing in the shape either of blood or spirits from the hen, for the purpose of forming its so called sanguineous parts and its feathers; as most clearly appears to any one who looks on with an unbiassed mind. From observations afterwards to be communicated, I believe indeed that it will be held as sufficiently proven that even the fœtus of viviparous animals still contained in the uterus is not nourished by the blood of the mother and does not vegetate through her spirit; but boasts of its own peculiar vital principle and powers, and its own blood, like the chick in ovo.

With reference to the matter which the embryo obtains from its male and female parent, however, and the way and manner of generation as commonly discoursed of in the schools, viz.: that conception is produced or becomes prolific from mixture of the genitures and their mutual action and passion, as also of the seminal fluid of the female, and the parts which are spoken of as sanguineous and spermatic, numerous and striking observations afterwards to be related have compelled me to adopt opinions at variance with all such views. At this time I shall only say that I am greatly surprised how physicians, particularly those among them who are conversant with anatomy, should pretend to support their opinions by means of two arguments especially, which rightly understood, seem rather to prove the opposite; viz., from the shock and resolution of the forces and the effusion of fluid which women at the moment of the sexual orgasm frequently experience, they argue that all women pour out a seminal fluid, and that this is necessary to generation.

But passing over the fact that the females of all the lower animals, and all women, do not experience any such emission of fluid, and that conception is nowise impossible in cases where it does not take place, for I have known several, who without anything of the kind were sufficiently prolific, and even some who after experiencing such an emission and having had great enjoyment, nevertheless appeared to have lost somewhat of their wonted fecundity; and then an infinite number of instances might be quoted of women who, although they have great satisfaction in intercourse, still emit nothing, and yet conceive; passing over these facts, I say, I cannot but express surprise at those especially, who, conceiving such an emission on the part of the female necessary to conception, have not adverted to the fact that the fluid emitted is discharged, cast out, and is particularly abundant about the clitoris and orifice of the vulva; that it is seldom poured out within the vulva, never within the uterus, and so as to be mingled with the semen of the male; moreover, it is of a mere serous or ichorous consistency, like urine, by no means thick and apparently unctuous, like the spermatic matter of the male. But how shall we suppose that to be of use internally which is discharged externally? Or shall we say that this humour, as if bidding the uterus farewell, is taken to the verge of the vulva, that it may be then recalled with greater favour by the uterus?

The other argument is drawn from the genital organs of women, the testes, to wit, and vasa spermatica, præparantia et deferentia, which are held to serve for the preparation of the spermatic fluid. I, for my part, greatly wonder how any one can believe that from parts so imperfect and obscure, a fluid like the semen, so elaborate, concoct and vivifying, can ever be produced, endowed with force and spirit and generative influence adequate to overcome that of the male; for this is implied in the discussion concerning the predominance of the male or the female, as to which of them is to become the agent and efficient cause, which the matter and pathic principle. How should such a fluid get the better of another concocted under the influence of a heat so fostering, of vessels so elaborate, and endowed with such vital energy?—how should such a fluid as the male semen be made to play the part of mere matter?—But of these things more hereafter.

Meantime it is certain that the egg of the hen is not engendered from any such discharge of fluid during sexual intercourse, although after connexion, and brimful of satisfaction, she shakes herself for joy, and, as if already possessed of the richest treasure, as if gifted by supreme Jove the preserver with the blessing of fecundity, she sets to work to prune and ornament herself. The pigeon, particularly that kind which comes to us from Africa, expresses the satisfaction she feels from intercourse in a remarkable manner; she leaps, spreads her tail, and sweeps the ground with its extremity, she pecks and prunes her feathers—all her actions are as if she felt raised to the summit of felicity by the gift of fruitfulness.

We have said that the primary matter of the egg does not consist of blood as Aristotle would have it, neither does it proceed from any mixture of the male and female seminal fluids. Whence it truly originates we have already stated in part in our history; and we shall by and by have occasion to speak of the subject more at length when we come to treat generally of the matter from which every conception is originally produced.

EXERCISE THE THIRTY-FIFTH.

In how far is the fowl efficient in the generation of the egg, according to Aristotle? And wherefore is the concurrence of the male required?

It has been already stated that the cock and hen are the two principles in the generation of the egg, although of the manner in which they are so I am of a different opinion from Aristotle and medical authorities. From the production of the egg we have clearly shown that the female as well as the male was efficient, and that she had within her a principle whence motion and the faculty of forming flowed; although in the sexual act the male neither confers the matter, nor does the female eject any semen whence the egg is constituted. It is consequently manifest, in some animals at least, that nature has not, on account of the distinction into male and female, established it as a law that the one, as agent, should confer form, the other, as passive, supply matter, as Aristotle apprehended; nor yet that during intercourse each should contribute a seminal fluid, by the mixture of which a conception or ovum should be produced, as physicians commonly suppose.

Now since everything that has been delivered by the ancients on generation is comprehended in these two opinions, it appears to have escaped every one up to this time, first, why the hen by herself does not generate, like vegetables, but requires a male to be associated with her in the work; and then how the conception or ovum is procreated by the male and the female together, or what either of them contributes to the process, and for what end intercourse was established.

Aristotle, in opposition to the entire tenor of his hypothesis, viz. that the male is to be regarded as the agent, the female as supplying the matter only, when he sees that eggs are actually produced by hens without the concurrence of the male, is compelled to admit that the female is likewise efficient; he was farther not ignorant of the fact that an egg even when extruded could preserve itself, nourish itself, increase in size and produce an embryo, as happens with the eggs of fishes; and he has besides accorded a vital principle to an egg, even to a hypenemic one. But he endeavours to explain to what extent a female is efficient, and how a hypenemic egg is endowed with a vital principle, in the passage where he says[226]: “Hypenemic eggs admit of generation to a certain point; for that they can ever go the length of producing an animal is impossible, this being the work of the senses [the sensible soul]. But females and all things that live, as already repeatedly stated, possess the vegetative soul. Wherefore the hypenemic egg as a vegetable is perfect, but as an animal it is imperfect.” By this he seems to insinuate that the hypenemic egg is possessed of a vegetative soul, inasmuch as this is inherent in all things that live, and an egg is alive. In like manner he ascribes to the hen the power of creating and of conferring the vegetative soul; because all females acquire this virtue, so that a hypenemic egg in so far as it lives as a vegetable is perfect, in so far as it is an animal however it is imperfect. As if a male were not required that a conception or ovum should be produced, and produced perfect; but that from this ovum an animal should be engendered. Not, I say, that an egg be produced as perfect in all respects as is the conception of a vegetable; but that it should be imbued with the animal principle. The egg, consequently, is formed by the hen, but it is made prolific by the cock.

Aristotle adds in the same place: “There is a distinction of sexes through the whole class of birds. And therefore it happens that the hen perfects her egg, not yet influenced by the intercourse of the male, in so far as it is a plant; but as it is not a plant, there she does not perfect it: nor does anything come of it which engenders. For neither has it arisen simply, like the seed of a plant, nor like an animal conception, by intercourse.” He is here speaking of the wind egg; by and by he adds: “But those eggs that are conceived through intercourse are already characterized in a portion of the albumen: such eggs become fruitful through the male which first copulated, for they are then supplied with both principles.”

By this he seems to confess that the female is also effective in the work of generation, or is possessed of the faculty of engendering; because in every female there inheres a vegetative soul, whose faculty it is to engender. And, therefore, when he is speaking of the differences between the male and female, he still acknowledges both as generative; for he says: “We call that animal male which engenders in another, female that which engenders in itself.” From his own showing, therefore, both engender; and as there is a vegetative soul inherent in both, so is there also its faculty of generation. But how they differ has already been shown in the History of the Egg: the hen generates of herself without the concurrence of the cock, as a plant out of itself produces fruit; but it is a wind egg that is thus produced: it is not made fruitful without the concurrence of the cock either preceding or succeeding. The female generates, then, but it is only up to a certain mark, and the concurrence of the male is requisite that this faculty of engendering be made complete, that she may not only lay an egg, but such an egg as will, under favorable circumstances, produce a pullet. The male appears to be ordained by nature to supply this deficiency in the generative powers of the female, as will be clearly shown by and by, and that that which the female of herself cannot accomplish, viz. the production of a fruitful egg, may be supplied and made good by the act of the male, who imparts this virtue to the fowl or the egg.

EXERCISE THE THIRTY-SIXTH.

The perfect hen’s egg is of two colours.

Every egg, then, is not perfect; but some are to be held imperfect because they have not yet attained their true dimensions, which they only receive when extruded; others are imperfect because they are yet unprolific, and only acquire a fertilizing faculty from without, such are the eggs of fishes. Other eggs again are held imperfect by Aristotle, because they are of one colour only, inasmuch as perfect eggs consist of yelk and albumen, and are of two colours, as if better concocted, more distinct in their parts, endowed with higher heat. The eggs that are called centenine or hundredth eggs, and which Fabricius[227] will have it are engendered of certain remainders of albumen, are of one colour only, and by reason of their deficiency of heat and their weakness, are regarded as imperfect. Of all eggs, there are none more perfect than those of the hen, which are produced complete in all their fluids and appendages, of proper size and fruitful.

Aristotle assigns the following reason wherefore some eggs are of two colours, others of one hue only:[228] “In the hotter animals those things from which the principles of their origin are derived, are distinct and separate from those which furnish their nutrition; now the one of these is white, the other is yellow.” As if the chick derived its origin from the albumen and was nourished by the vitellus alone. In the same place he proceeds thus: “That part which is hot contributes properly to the form in the constitution of the extremities; but the part that is more earthy, and is further removed, supplies material for the trunk. Whence in eggs of two colours the animal derives its origin from the white, for the commencement of animal existence is in the white; but the nourishment is obtained from the yellow.” He consequently thinks that this is the reason why these fluids are distinct, and why eggs are produced of two colours.

Now these ideas are partly true, partly false. It is not true, for instance, that the embryo of the common fowl is first formed from the albumen and then nourished by the vitellus; for, from the history of the formation of the chick in ovo, from the course of the umbilical vessels and the distribution of their branches, which undoubtedly serve for obtaining nourishment, it obviously appears that the constituent matter, and the nutriment are supplied to the chick from its first formation by the yelk, as well as the white; the fluid which we have called the colliquament seems farther to be supplied, not less by the vitellus than the albumen; a certain portion of both the fluids seems, in fact, to be resolved. And then the spot, by the expansion of which the colliquament is formed in the first instance, and which we have called the eye, appears to be impressed upon the membrane of the vitellus.

The distinction into yellow and white, however, seems to be a thing necessary: these matters, as they are undoubtedly of different natures, appear also to serve different offices; they are therefore completely separate in the perfect egg, one of them being more the other less immediately akin to proper alimentary matter; by the one the fœtus is nourished from the very beginning, by the other it is nourished at a later period. For it is certain, as Fabricius asserts, and as we afterwards maintain, that both of them are truly nutritious, the albumen as well as the vitellus, the albumen being the first that is consumed. I therefore agree with Aristotle against the physicians, that the albumen is the purer portion of the egg, the better concocted, the more highly elaborated; and, therefore, whilst the egg is getting perfected in the uterus, is the albumen as the hotter portion poured around in the circumference, the yelk or more earthy portion subsiding to the centre. For the albumen appears to contain the larger quantity of animal heat, and so to be nutriment of a more immediate kind. For like reasons it is probable that the albumen is purer and better concocted externally than it is internally.

When medical writers affirm that the yelk is the hotter and more nutritious portion of the egg, this I imagine is meant as it affords food to us, not as it is found to supply the wants of the chick in ovo. This, indeed, is obvious from the history of the formation of the chick, by which the thin albumen is absorbed and used up sooner than the thick, as if it formed the more appropriate aliment, and were more readily transmuted into the substance of the embryo, of the chick that is to be. The yelk, therefore, appears to be a more distant or ultimate aliment than the albumen, the whole of which has been used up before any notable portion of the vitellus is consumed. The yelk, indeed, is still found inclosed within the abdomen of the chick after its exclusion from the shell, as if it were destined to serve the new being in lieu of milk for its sustenance.

Eggs, consisting of white and yellow, are therefore more perfect, as more distinct in constitution, and elaborated by a higher temperature. For in the egg there must be included, not only the matter of the chick but also its first nutriment; and what is provided for a perfect animal, must, itself, be perfect and highly elaborated; as that is, in fact, which consists of different parts, some of which, as already stated, are prior and purer, and so more easy of digestion; others posterior, and therefore more difficult of transmutation into the substance of the chick. Now the yelk and albumen differ from one another by such kinds of distinction. Perfect eggs are, consequently, of two colours: they consist of albumen and yelk, as if these constituted fluids of easier or more difficult digestion, adapted to the different ages and vigour of the chick.

EXERCISE THE THIRTY-SEVENTH.

Of the manner in which the egg is increased by the albumen.

From the history it appears that the rudiments of the eggs in the ovary are of very small size, mere specks, smaller than millet seeds, white and replete with watery fluid: these specks, however, by and by, become yelks, and then surround themselves with albumen.

Aristotle seems to think that the albumen is generated in the way of secretion from the vitellus. It may be well to add his words:[229] “The sex,” he says, “is not the cause of the double colour, as if the white were derived from the male, the yellow from the female; both are furnished by the female. But one of them is hot, the other is cold. Now these two portions are distinct in animals, fraught with much heat; in those that are not so fraught the eggs are not thus distinct. And this is the reason why the conceptions of these are of one colour. But the semen of the male alone sets the conception; therefore is the conception of the bird small and white in the first instance; but in the course of time, and when there is a larger infusion of blood, it becomes entirely yellow; and, last of all, when the heat declines, the white portion, as a humour of equal temperature surrounds it on every side. For the white portion of the egg is, by its nature, moist, and includes animal heat in itself; and it is for this reason that it is seen in the circumference, the yellow and earthy portion remaining in the interior.”

Fabricius,[230] however, thinks that “the albumen only adheres to the vitellus by juxtaposition. For while the yelk is rolled through the second uterus and gradually descends, it also gradually assumes to itself the albumen which is there produced, and made ready, that it may be applied to the yelk; until the yelk having passed the middle spirals and reached the last of them, already surrounded with the albumen, it now surrounds itself with the membranes and shell.” Fabricius will therefore have it that the egg increases in a two-fold manner: “partly by means of the veins, as concerns the vitellus, and partly by an appositive increase, as regards the albumen.” And, among other reasons, this was perchance one for the above opinion: that when an egg is boiled hard the albumen is readily split into layers lying one over another. But this also occurs to the yelk still connected with the ovary, when boiled hard.

Wherefore, taught by experience, I rather incline to the opinion of Aristotle; for the albumen is not merely perceived as added in the way Fabricius will have it, but fashioned also, distinguished by chalazæ and membranes, and divided into two different portions; and all this in virtue of the inherence of the same vegetative vital principle by which the egg is more conspicuously divided into two distinct substances—a yelk and a white. For the same faculty that presides over the formation of the egg in general, presides over the constitution of each of its parts in particular. Neither is it altogether true that the yelk is first formed and the albumen added to it afterwards; for what is seen in the ovary is not the vitellus of the egg, but rather a compound containing the two liquids mingled together. It has the colour of the vitellus, indeed, but in point of consistence it is more like the albumen; and when boiled hard it is not friable like the proper yelk, but, like the white, is concreted, jelly-like, and seen to be composed of thin lamellæ; and it has a kind of white papula, or spot, in the middle.

Aristotle seems to derive this separation from the dissimilar nature of the yelk and white; for he says,[231] as we have already stated, that if a number of eggs be thrown into a pan and boiled, in such wise that the heat shall not be quicker than the separation of the eggs, (citatior quam ovorum distinctio,) the same thing will take place in the mass of eggs which occurs in the individual egg: the whole of the yelks will set in the middle, the whites round about them.

This I have myself frequently found to be true on making the trial, and it is open to any one to repeat the experiment; let him only beat yelks and whites together, put the mixture into a dutch oven, or between two plates over the fire, and having added some butter, cause it to set slowly into a cake, he will find the albumen covering over the yelks situated at the bottom.

EXERCISE THE THIRTY-EIGHTH.

Of what the cock and hen severally contribute to the production of the egg.

Both cock and hen are to be reputed parents of the chick; for both are necessary principles of an egg, and we have proved both to be alike its efficient: the hen fashions the egg, the cock makes it fertile. Both, consequently, are instruments of the plastic virtue by which this species of animal is perpetuated.

But as in some species there appears to be no occasion for males, females sufficing of themselves to continue the kind; so do we discover no males among these, but females only, containing the fertile rudiments of eggs in their interior; in other species, again, none but males are discovered which procreate and preserve their kinds by emitting something into the mud, or earth, or water. In such instances nature appears to have been content with a single sex, which she has used as an instrument adequate to procreation.

Another class of animals has a generative fluid fortuitously, as it were, and without any distinction of sex; the origin of such animals is spontaneous. But “as some things are made by art, and some depend on accident, health for example,”[232] so also some semen of animals is not produced by the act of an individual agent, as in the case of a man engendered by a man; but in some sort univocally, as in those instances where the rudiments and matter, produced by accident, are susceptible of taking on the same motions as seminal matter, as in “animals which do not proceed from coitus, but arise spontaneously, and have such an origin as insects which engender worms.”[233] For as mechanics perform some operations with their unaided hands, and others not without the assistance of particular tools; and as the more excellent and varied and curious works of art require a greater variety in the form and size of the tools to bring them to perfection, inasmuch as a greater number of motions and a larger amount of subordinate means are required to bring more worthy labours to a successful issue—art imitating nature here as everywhere else, so also does nature make use of a larger number and variety of forces and instruments as necessary to the procreation of the more perfect animals. For the sun, or Heaven, or whatever name is used to designate that which is understood as the common generator or parent of all animated things, engenders some of themselves, by accident, without an instrument, as it were, and equivocally; and others through the concurrence of a single individual, as in those instances where an animal is produced from another animal of the same genus which supplies both matter and form to the being engendered; so in like manner in the generation of the most perfect animals where principles are distinguished, and the seminal elements of animated beings are divided, a new creation is not effected save by the concurrence of male and female, or by two necessary instruments. Our hen’s egg is of this kind; to its production in the perfect state the cock and the hen are necessary. The hen engenders in herself, and therefore does she supply place and matter, nutriment and warmth; but the cock confers fecundity; for the male, as Aristotle says,[234] always perfects generation, secures the presence of a sensitive vital principle, and from such an egg an animal is engendered.

To the cock, therefore, as well as to the hen, are given the organs requisite to the function with which he is intrusted; in the hen all the genital parts are adapted to receive and contain, as in the cock they are calculated to give and immit, or prepare that which transfers fecundity to the female, he engendering, as it were, in another, not in himself.

When we anatomize the organs appropriated to generation, therefore, we readily distinguish what each sex contributes in the process; for a knowledge of the instruments here leads us by a direct path to a knowledge of their functions.

EXERCISE THE THIRTY-NINTH.

Of the cock and the particulars most remarkable in his constitution.

The cock, as stated, is the prime efficient of the perfect or fruitful hen’s egg, and the chief cause of generation: without the male no chick would ever be produced from an egg, and in many ovipara not even would any egg be produced. It is, therefore, imperative on us that we look narrowly into his offices and uses, and inquire particularly what he contributes to the egg and chick, both in the act of intercourse and at other times.

It is certain that the cock in coition emits his ‘geniture,’ commonly called semen, from his sexual parts, although he has no penis, as I maintain; because his testes and long and ample vasa deferentia are full of this fluid. But whether it issues in jets, with a kind of spirituous briskness and repeatedly as in the hotter viviparous animals, or not, I have not been able to ascertain. But as I do not find any vesiculæ containing semen, from which, made brisk and raised into a froth by the spirits, it might be emitted; nor any penis through whose narrower orifice it might be forcibly ejaculated, and so strike upon the interior of the hen; and particularly when I see the act of intercourse so rapidly performed between them; I am disposed to believe that the parts of the hen are merely moistened with a very small quantity of seminal fluid, only as much as will adhere to the orifice of the pudenda, and that the prolific fluid is not emitted by any sudden ejaculation; so that whilst among animals repeated ejaculations take place during the same connection, among birds, which are not delayed with any complexity of venereal apparatus, the same object is effected by repeated connections. Animals that are long in connection, copulate rarely; and this is the case with the swan and ostrich among birds. The cock, therefore, as he cannot stay long in his connections, supplies by dint of repeated treadings the reiterated ejaculations of the single intercourse in other animals; and as he has neither penis nor glans, still the extremities of the vasa deferentia, inflated with spirits when he treads, become turgid in the manner of a glans penis, and the orifice of the uterus of the hen, compressed by them, her cloaca being exposed for the occasion, is anointed with genital fluid, which consequently does not require a penis for its intromission.

We have said, however, that such was the virtue of the semen of the cock, that not only did it render the uterus, the egg in utero, and the vitelline germ in the ovary, but the whole hen prolific, so that even the germs of vitelli, yet to be produced, were impregnated.

Fabricius has well observed, that the quantity of spermatic fluid contained in the testes and vasa deferentia of the cock was large; not that the hen requires much to fecundate each of her eggs, but that the cock may have a supply for the large number of hens he serves and for his repeated addresses to them.

The shortness and straight course of the spermatic vessels in the cock also assist the rapid emission of the spermatic fluid: anything that must pass through lengthened and tortuous conduits of course escapes more slowly and requires a greater exercise of the impelling power or spirit to force it away.

Among male animals there is none that is more active or more haughty and erect, or that has stronger powers of digestion than the cock, which turns the larger portion of his food into semen; hence it is that he requires so many wives,—ten or even a dozen. For there are some animals, single males of which suffice for several females, as we see among deer, cattle, &c.; and there are others, of which the females are so prurient that they are scarcely satisfied with several males, such as the bitch and the wolf; whence prostitutes were called lupæ or wolves, as making their persons common; and stews were entitled lupanaria. Whilst some animals, of a more chaste disposition, live, as it were, in the conjugal estate, so that the male is married to a single female only, and both take part in providing for the wants of the family; for since nature requires that the male supply the deficiencies of the female in the work of generation, and as she alone in many cases does not suffice to cherish and feed and protect the young, the male is added to the wife that he may take part in the burthen of bringing up the offspring. Partridges lead a wedded life, because the females alone cannot incubate such a number of eggs as they lay, (so that they are said, by some, to make two nests,) nor to bring up such a family as by and by appears without assistance. The male pigeon also assists in building the nest, takes his turn in incubating the eggs, and is active in feeding the young. In the same way many other instances of conjugal life among the lower animals might be quoted, and indeed we shall have occasion to refer to several in what yet remains to be said.

Those males, among animals, which serve several females, such as the cock, have an abundant secretion of seminal fluid, and are provided with long and ample vasa deferentia. And at whatever time or season the clustered rudimentary papulæ in the ovary come to maturity and require fecundation, that they may go on to be turned into perfect eggs, the males will then be found to have an abundance of seminal fluid, and the testicles to enlarge and become conspicuous in the very situation to which they transfer their fecundating influence, viz. the præcordia. This is remarkable in fishes, birds, and the whole race of oviparous animals; the males of which teem with fecundating seminal fluid at the same precise seasons as the females become full of eggs.

Whatever parts of the hen, therefore, are destined by nature for purposes of generation, viz. the ovary, the infundibulum, the processus uteri, the uterus itself, and the pudenda; as also the situation of these parts, their structure, dimensions, temperature, and all that follows this; all these, I say, are either subordinate to the production and growth of the egg, or to intercourse and the reception of fecundity from the male; or, for the sake of parturition, to which they conduce either as principal and convenient means, or as means necessary, and without which what is done could not be accomplished; for nothing in nature’s works is fashioned either carelessly or in vain. In the same way all the parts in the cock are fashioned subordinate to the preparation or concoction of the spermatic fluid, and its transference to the hen.

Now those males that are so vigorously constituted as to serve several females are larger and handsomer, and in the matter of spirit and arms excel their females in a far greater degree than the males of those that live attached to a single female. Neither the male partridge, nor the crow, nor the pigeon, is distinguished from the female bird in the same decided way as the cock from his hens, the stag from his does, &c.

The cock, therefore, as he is gayer in his plumage, better armed, more courageous and pugnacious, so is he replete with semen, and so apt for repeated intercourse, that unless he have a number of wives he distresses them by his frequent assaults; he not only invites but compels them to his pleasure, and leaping upon them at inconvenient and improper seasons, (even when they are engaged in the business of incubation) and wearing off the feathers from their backs, he truly does them an injury. I have occasionally seen hens so torn and worn by the ferocious addresses of the cock, that with their backs stript of feathers and laid bare in places, even to the bone, they languished miserably for a time and then died. The same thing also occurs among pheasants, turkeys, and other species.

EXERCISE THE FORTIETH.

Of the hen.

There are two instruments and two first causes of generation, the male and the female—for to the hen seems to belong the formation of the egg, as to the cock the fertilizing principle. In the act of intercourse, then, of these two, that which renders the egg fruitful is either transmitted from the male to the female, or by means of coition is generated in the hen. The nature of this principle, however, is no less difficult to ascertain than are the particulars of its communication, whether, for instance, we suppose such communication to take place with the whole system of the hen, or simply with her womb, or with the egg already formed, or further, with all the eggs now commencing and hereafter about to commence their existence in the ovary. For it is probable, from what I have formerly mentioned, and also from the experiment of Fabricius,[235] that but a few acts of intercourse, and the consorting of the hen with the cock for some days, are sufficient to fecundate her, or at least her womb, during the whole year. And so far I can myself affirm, from my own observation, to wit, that the twentieth egg laid by a hen, after separation from the cock, has proved prolific. So that, in like manner as it is well known that, from the seed of male fishes shed into the water, a large mass of ova is impregnated, and that in dogs, pigs, and other animals, a small number of acts of intercourse suffice for the procreation of many young ones, (some even think it well established, that if a bitch have connexion more than three or four times, her fruitfulness is impaired, and that more females than males are then engendered), so may the cock, by a few treadings, render prolific not only the egg in the womb, but also the whole ovarium, and, as has been often said, the hen herself. Nay, what is more remarkable, and indeed wonderful, it is said that in Persia,[236] on cutting open the female mouse, the young ones still contained in the belly are already pregnant; in other words, they are mothers before they are born! as if the male rendered not only the female fruitful, but also impregnated the young which she had conceived; in the same way as our cock fertilizes not merely the hen, but also the eggs which are about to be produced by her.

But this is confidently denied by those physicians who assert that conception is produced from a mixture of the seed of each sex. And hence Fabricius,[237] although he affirms that the seed of the cock ejected in coition never does, nor can, enter the cavity of the womb, where the egg is formed, or takes its increase, and though he plainly sees that the eggs when first commencing in the ovarium are, no less than those which exist in the womb, fecundated by the same act of coition, and that of these no part could arise from the semen of the cock, yet has he supposed that this semen, as if it must needs be present and permanent, is contained during the entire year in the “bursa” of the fruitful hen, and reserved in a “foramen cæcum.” This opinion we have already rejected, as well because that cavity is found in the male and female equally, as because neither there, nor anywhere else in the hen, have we been able to discover this stagnant semen of the cock; as soon as it has performed its office, and impressed a prolific power on the female, it either escapes out of the body, or is dissolved, or is turned into vapour and vanishes. And although Galen,[238] and all physicians with him, oppose by various reasonings this dissolving of the semen, yet, if they carefully trace the anatomical arrangement of the genital parts, and at the same time weigh other proofs of the strongest kind, they must confess that the semen of the male, as it is derived from the testicles through the vasa deferentia, and as it is contained in the vesiculæ seminales, is not prolific unless it be rendered spiritual and effervesce into a frothy nature by the incitement of intercourse or desire. For it is not, as Aristotle[239] bears witness, its bodily form, or fire, or any such faculty, that renders the semen prolific, but the spirit which is contained in it, and the nature which inheres in it, bearing a proportion to the element of the stars. Wherefore, though we should allow with Fabricius that the semen is retained in the “bursa,” yet, when that prolific effervescence or spirit had been spent, it would forthwith be useless and sterile. Hence, too, physicians may learn that the semen of the male is the architect of the progeny, not because the first conception is embodied out of it, but because it is spiritual and effervescent, as if swelling with a fertilising spirit, and a preternatural influence. For otherwise the story of Averrhöes, of the woman who conceived in a bath, might bear an appearance of truth. But of these things more in their proper place.

In the same manner then as the egg is formed from the hen, so is it probable, that from the females of other animals, as will hereafter be shown, the first conceptions take both material and form; and that, too, some little time after the semen of the male has been introduced, and has disappeared again. For the cock does not confer any fecundity on the hen, or her eggs, by the simple emission of his semen, but only in so far as that fluid has a prolific quality, and is imbued with a plastic power; that is to say, is spiritual, operative, and analogous to the essence of the stars. The male, therefore, is no more to be considered the first principle, from which conceptions and the embryo arise, because he is capable of secreting and emitting semen, than is the female, which creates an egg without his assistance. But it is on this consideration rather that he is entitled to his prerogative, that he introduces his semen, imbued as it is with the spirit and the virtue of a divine agent, such as, in a moment of time, performs its functions, and conveys fertility. For, as we see things suddenly set on fire and blasted by a spark struck from a flint, or the lightning flashing from a cloud, so equally does the seed of the male instantly affect the female which it has touched with a kind of contagion, and transfer to her its prolific quality, by which it renders fruitful in a moment, not only the eggs, but the uterus also, and the hen herself. For an inflammable material is not set on fire by the contact of flame more quickly, than is the hen made pregnant by intercourse with the cock. But what it is that is transferred from him to her, we shall afterwards find occasion to speak of, when we treat this matter specially and at greater length.

In the meantime we must remark, that, if it be derived from the soul, (for whatever is fruitful is probably endowed also with a soul; and we have said before, that the egg, in Aristotle’s opinion, as well as the seeds of plants, has a vegetative soul,) that soul, or at all events the vegetative one, must be communicated as a graft, and transferred from the male to the female, from the female to the egg, from the egg to the fœtus; or else be generated in each of these successively by the contagion of coition.

The subject, nevertheless, seems full of ambiguity; and so Aristotle, although he allows that the semen of the male has such great virtue, that a single emission of it suffices for fecundating very many eggs at the same time, yet, lest this admission should seem to gainsay the efficacy of frequent repetitions of intercourse, he further says,[240] “In birds, not even those eggs which arise through intercourse can greatly increase in size, unless the intercourse be continued; and the reason of this is, that, as in women, the menstrual excretion is drawn downwards by sexual intercourse, (for the uterus, becoming warm, attracts moisture, and its pores are opened,) so also does it happen with birds, in which the menstrual excrement, because it accumulates gradually, and is retained above the cincture, and cannot escape, from being in small quantity, only passes off when it has reached the uterus itself. For by this is the egg increased, as is the fœtus of the viviparous animal by that which flows through the umbilicus. For almost all birds, after but a single act of intercourse, continue to produce eggs, but they are small.”

Now, so far perhaps would the opinion of Aristotle be correct, that more and larger eggs are procured by frequently-repeated intercourse; because, as he says, there may be “a flow of more fruitful material to the womb, when warmed by the heat of coition;” not however that frequent coition must necessarily take place in order to render the eggs that are laid prolific. For experience, as we have said, teaches the contrary, and the reason which he alleges does not seem convincing; since the rudiments of eggs are not formed in the uterus from menstrual blood, which is found in no part of the hen, but in the ovary, where no blood pre-exists, and originate as well without, as along with the intercourse of the cock.

The hen, as well as all other females, supplies matter, nutrition, and place to the conception. The matter, whence the rudiments of all eggs are produced in the ovary and take their increase, seems to be the very same from which all the other parts of the hen, namely, the fleshy, nervous, and bony structures, as well as the head and the rest of the members, are nourished and grow. Nourishment is in fact conveyed to each single papula and yelk contained in the ovary by means of vessels, in the same way precisely as to all the other parts of the hen. But the place where the egg is provided with membranes, and perfected by the addition of the chalazæ and shell, is the uterus.

But that the hen neither emits any semen during intercourse, nor sheds any blood into the cavity of the uterus, and that the egg is not formed in the mode in which Aristotle supposed a conception to arise, nor, as physicians imagine, from a mixture of the seminal fluids; as also that the semen of the cock does not penetrate into, nor is attracted towards, the cavity of the uterus of the hen, is all made manifestly clear by this one observation, namely, that after intercourse there is nothing more to be found in the uterus, than there was before the act. And when this shall have been afterwards clearly established and demonstrated to be true of all kinds of animals, which conceive in a uterus, it will at the same time be equally evident, that what has hitherto been handed down to us from all antiquity on the generation of animals, is erroneous; that the fœtus is not constituted of the semen either of the male or female, nor of a mixture of the two, nor of the menstrual blood, but that in all animals, as well in the prolific conception as after it, the same series of phenomena occur as in the generation of the chick from the egg, and as in the production of plants from the seeds of their several kinds. For, besides that, it appears the male is not required as being in himself agent, workman, and efficient cause; nor the female, as if she supplied the matter; but that each, male as well as female, may be said to be in some sort the operative and parent; and the fœtus, as a mixture of both, is created a mixed resemblance and kind. Nor is that true which Aristotle often affirms, and physicians take for granted, namely, that immediately after intercourse, something either of the fœtus or the conception may be found in the uterus, (for instance, the heart, the “three bullæ,” or some other principal part,) at any rate something—a coagulum, some mixture of the spermatic substances, or other things of the like kind. On the contrary, it is not till long after intercourse that the eggs and conception first commence their existence, among the greater number of animals, and these the most perfect ones; I mean in the cases where the females have been fruitful and have become pregnant. And that the female is prolific, before any conception is contained in the uterus, there are many indications, as will be hereafter set forth in the history of viviparous animals: the breasts enlarge, the uterus begins to swell, and by other symptoms a change of the whole system is discerned.

But the hen, though she have for the most part the rudiments of eggs in her before intercourse, which are afterwards by this act rendered fruitful, and there be, therefore, something in her immediately after coition, yet even when she, as in the case of other animals, has as yet no eggs ready prepared in the ovary, or has at the time of the intercourse got rid of all she had, yet does she by and by, even after some lapse of time, as if in possession of both principles or the powers of both sexes, generate eggs by herself after the manner of plants; and these (I speak from experience) not barren, but prolific.

Nay, what is more, if you remove all the eggs from beneath a hen that has been fecundated and is now sitting, (after having already laid all her eggs, and no more remain in the ovary,) she will begin to lay again; and the eggs thus laid will be prolific, and have both principles inherent in them.

EXERCISE THE FORTY-FIRST.

Of the sense in which the hen may be called the “prime efficient:” and of her parturition.

It has already been said, that the hen is the efficient cause of generation, or an instrument of Nature in this work, not indeed immediately, or of herself; but when rendered prolific by commission from, and in virtue of the male. But as the male is considered by Aristotle to be the first principle of generation on his own merits, because the first impulse toward generation proceeds from him, so may the hen in some measure be put down as the first cause of generation; inasmuch as the male is undoubtedly inflamed to venery by the presence of the female. “The female fish,” says Pliny,[241] “will follow the male at the season of intercourse, and strike his belly with her nose; at the spawning time the male will do the like to the female.” I have myself at times seen male fishes in shoals following a female that was on the point of spawning, in the same way as dogs pursue a bitch, that they might sprinkle the ova just laid with their milk or seed. But this is particularly to be remarked in the more wanton and lascivious females, who stir up the dormant fires of Cupid, and inspire a silent love; hence it is that the common cock, so soon as he sees one of his own hens that has been absent for ever so short time, or any other stranger-hen, forthwith feels the sting of desire, and treads her. Moreover, victorious in a battle, although wounded and tired from the fight, he straightway sets about treading the wives of his vanquished foe one after another. And that he may further feed the flame of love thus kindled in his breast, by various gesticulations, incitements, and caresses, often crowing the while, calling his hens to him, approaching and walking round them, and tripping himself with his wings, he entices his females to intercourse as by a kind of fascination. Such are the arts of the male; but sometimes a certain sullenness of the female, and an apparent disinclination on her part, contribute not a little to arouse the ardour of the male and stimulate his languishing desire, so that he fills her more quickly and more copiously with prolific spirit. But of allurements of this kind, and in what degree they promote conception, we shall speak more hereafter. For, if you carefully weigh the works of nature, you will find that nothing in them was made in vain, but that all things were ordered with a purpose and for the sake of some good end.

Almost all females, though they have pleasure in the act of intercourse and impregnation, suffer pain in parturition. But the reverse is the case with the hen, who loudly complains during intercourse and struggles against it; but in parturition, although the egg be very large in comparison with the body and the orifice of the uterus, and it does nothing to further its exit, (as is customary with the young of viviparous animals,) yet she brings forth easily and without pain, and immediately afterwards commences her exultations; and with her loud cackling calls the cock as it seems to share in her triumph.

But, although many rudiments of eggs are found in the hen’s ovary, of various sizes and in different stages, so that some are larger and nearer to maturity than others, yet all of them appear to be fecundated, or to receive the prolific faculty from the tread of the cock at the same time and in the same degree. And though a considerable time elapse (namely, thirty or more days) before the common hen or hen-partridge lay all the eggs which she has conceived, yet in a stated time after the mother has begun to sit upon them (say twenty or two and twenty days) all the young are hatched nearly at the same time; nor are they less perfect than if they had commenced their origin simultaneously, from the period of one and the same conception, as the whelps of bitches do.

And while we are here, and while I think how small are the prolific germs of eggs, mere papulæ and exudations less than millet-seeds, and contemplate the full proportions of the cock that springs from thence, his fine spirit, and his handsome plumage, I cannot but express my admiration that such strength should be reposed in the nature of things in such insignificant elements, and that it has pleased the omnipotent Creator out of the smallest beginnings to exhibit some of his greatest works. From a minute and scarce perceptible papula springs the hen, or the cock, a proud and magnificent creature. From a small seed springs a mighty tree; from the minute gemmule or apex of the acorn, how wide does the gnarled oak at length extend his arms, how loftily does he lift his branches to the sky, how deeply do his roots strike down into the ground! “It is in truth a great miracle of nature,” says Pliny,[242] “that from so small an origin is produced a material that resists the axe, and that supplies beams, masts, and battering-rams. Such is the strength, such the power of nature!” But in the seeds of all plants there is a gemmule or bud of such a kind, so small that if the top only, a very point, be lost, all hope of propagation is immediately destroyed; in so small a particle does all the plastic power of the future tree seem lodged! The provident ant by gnawing off this little particle stores safely in her subterraneous hoard the grain and other seeds she gathers, and ingeniously guards against their growing: “The cypress,” adds Pliny, in the same place, “bears a seed that is greatly sought after by the ant; which makes us still further wonder, that the birth of mighty trees should be consumed in the food of so small an animal.” But on these points we shall say more when we show that many animals, especially insects, arise and are propagated from elements and seeds so small as to be invisible, (like atoms flying in the air,) scattered and dispersed here and there by the winds; and yet these animals are supposed to have arisen spontaneously, or from decomposition, because their ova are nowhere to be found. These considerations, however, may furnish arguments to that school of philosophy which teaches that all things are produced from nothing; and indeed there is hardly any ascertainable proportion between the rudiment and the full growth of any animal.

Nor should we so much wonder what it is in the cock that preserves and governs so perfect and beautiful an animal, and is the first cause of that entity which we call the soul; but much more, what it is in the egg, aye, in the germ of the egg, of so great virtue as to produce such an animal, and raise him to the very summit of excellence. Nor are we only to admire the greatness of the artificer that aids in the production of so noble a work, but chiefly the “contagion” of intercourse, an act which is so momentary! What is it, for instance, that passes from the male into the female, from the female into the egg, from the egg into the chick? What is this transitory thing, which is neither to be found remaining, nor touching, nor contained, as far as the senses inform us, and yet works with the highest intelligence and foresight, beyond all art; and which, even after it has vanished, renders the egg prolific, not because it now touches, but because it formerly did so, and that not merely in the case of the perfect and completed egg, but of the imperfect and commencing one when it was yet but a speck; aye, and makes the hen herself fruitful before she has yet produced any germs of eggs, and this too so suddenly, as if it were said by the Almighty, “Let there be progeny,” and straight it is so?

Let physicians, therefore, cease to wonder at what always excites their astonishment, namely, the manner in which epidemic, contagious, and pestilential diseases scatter their seeds, and are propagated to a distance through the air, or by some ‘fomes’ producing diseases like themselves, in bodies of a different nature, and in a hidden fashion silently multiplying themselves by a kind of generation, until they become so fatal, and with the permission of the Deity spread destruction far and wide among man and beast; since they will find far greater wonders than these taking place daily in the generation of animals. For agents in greater number and of more efficiency are required in the construction and preservation of an animal, than for its destruction; since the things that are difficult and slow of growth, decay with ease and rapidity. Seneca[243] observes, with his usual elegance, “How long a time is needed for conception to be carried out to parturition! with what labour and tenderness is an infant reared! to what diligent and continued nutrition must the body be subject, to arrive at adolescence! but by what a nothing is it destroyed! It takes an age to establish cities, an hour to destroy them. By great watching are all things established and made to flourish, quickly and of a sudden do they fall in pieces. That which becomes by long growth a forest, quickly, in the smallest interval of time, and by a spark, is reduced to ashes.” Nor is even a spark necessary, since by the solar rays transmitted through a small piece of glass and concentrated to a focus, fire may be immediately produced, and the largest things be set in flames. So easy is every thing to nature’s majesty, who uses her strength sparingly, and dispenses it with caution and foresight for the commencement of her works by imperceptible additions, but hastens to decay with suddenness and in full career. In the generation of things is seen the most excellent, the eternal and almighty God, the divinity of nature, worthy to be looked up to with reverence; but all mortal things run to destruction of their own accord in a thousand ways.

EXERCISE THE FORTY-SECOND.

Of the manner in which the generation of the chick takes place from the egg.

Hitherto we have considered the egg as the fruit and end; it still remains for us to treat of it as the seed and beginning. “We must now inquire,” says Fabricius[244], “how the generation of the chick results from the egg, setting out from that principle of Aristotle and Galen, which is, even conceded by all, to wit, that all things which are made in this life, are manifestly made by these three: workers, instruments, and matter.”

But since in natural phenomena, the work is not extrinsic, but is included in the matter, or the instruments, he concludes that we must take cognizance only of the agent and the matter.

As we are here about to shew in what manner the chick arises from the egg, however, I think it may be of advantage for me to preface this, by showing the number of modes in which one thing may be said to be made from another.

For so it will appear, more clearly and distinctly, after which of these generation takes place in the egg, and what are the right conclusions in regard to its matter, its instruments, and efficient cause.

Aristotle[245] has laid down that there are four modes in which one thing is made from another: “first, when we say that from day night is made, or from a boy a man, since one is after the other; secondly, when we say that a statue is made from brass, or a bed from wood, or any thing else from a certain material, so that the whole consists of something, which is inherent and made into a form; thirdly, as when from a musical man is made an unmusical one, or from a healthy, a sick one, or contraries in any way: fourthly, as Epicharmus exaggerates it, as of calumnies, cursing; of cursing, fighting. But all these are to be referred to that from whence the movement took its rise; for the calumny is a certain portion of the whole quarrel. Since then these are the methods in which one thing is made from another, it is clear that the seed is in one of two of these. For that which is born arises out of it, either as from matter, or as from the prime mover. For it is not, ‘as this is after that,’ in the same way as after the Panathenœa navigation; nor as ‘one contrary from another,’ for in such case, a thing would be born out of its contrary, because it is in a state of decay, and there must be something else as subject matter.”

By these words, Aristotle rightly infers, that the semen proceeding from the male, is the efficient or instrumental cause of the embryo; since it is no part of what is born, either in the first or third manner; (namely, as one thing is after another, or as it is out of its contrary;) nor does it arise from the subject matter.

But then, as he adds, in the same place, “that which comes out of the male in coition, is not with truth and propriety called semen, but rather geniture; and it is different from the seed properly so called. For that is called the geniture which, proceeding from the generant, is the cause which first promotes the beginning of generation. I mean in those creatures, which nature designed to have connection; but the seed is that which derives its origin from the intercourse of the two (i. e. of the male and female); such is the seed of all plants; and of some animals in which the sex is not distinct; it is the produce, as it were, of the male and female mixed together originally, like a kind of promiscuous conception;” and such as we have formerly in our history declared the egg to be, which is called both fruit and seed. For the seed and the fruit are distinct from each other, and in the relation of antecedent and consequent; the fruit is that which is out of something else, the seed is that out of which something else comes; otherwise both were the same.

It remains then, to inquire, in how many of the aforesaid ways the fœtus may arise, not indeed from the geniture of the male, but out of the true seed, or out of the egg or conception, which is in reality the seed of animals.

EXERCISE THE FORTY-THIRD.

In how many ways the chick may be said to be formed from the egg.

It is admitted, then, that the fœtus is formed from a prolific egg, as out of the proper matter, and as it were by the requisite agency, and that the same egg stands for both causes of the chick. For inasmuch as it derives its origin from the hen, and is considered as a fruit, it is the matter: but, in so far as it contains in its whole structure the prolific and plastic faculty infused by the male, it is called the efficient cause of the chick.

Moreover, not only as Fabricius supposed, are these, namely, the agent and the instrument, inseparably joined in one and the same egg, but it is also necessary, that the aliment by which the chick is nourished, be present in the same place. Indeed, in the prolific egg, these four are found together, to wit, the agent, the instrument, the matter, and the aliment, as we have shown in our history.

Wherefore, we say, that the chick is formed from the prolific egg in all the aforesaid ways, namely, as from matter, by an efficient, and by an instrument; and moreover, as a man grows out of a boy, as the whole is made up of its parts, and as a thing grows from its nutriment; a contrary thing springs from a contrary.

For after incubation is begun, as soon as by the internal motive principle a certain clear liquid which we have called the eye of the egg is produced, we say that that liquid is made as it were out of a contrary; in the same way as we suppose the chyle through concoction to be formed out of its contraries, (namely, crude articles of food,) and in the same way as we are said to be nourished by contraries; so, from the albumen is formed and augmented that to which we have given the names of the eye and the colliquament; and in the same manner, from that clear fluid do the blood and pulsating vesicle, the first particles of the chick, receive their being, nutrition, and growth. The nutriment, I say, is by the powers of an inherent and innate heat, assimilated by means of concoction, as it were out of a contrary. For the crude and unconcocted are contrary to the concocted and assimilated, as the unmusical man is to the musical, and the sick to the sound man.

And when the blood is engendered from the clear colliquament, or a clear fluid is produced from the white or the yelk, there is generation as regards the former, corruption as regards the latter; a transmutation, namely, is made from the extremes of contraries, the subject-matter all the while remaining the same. To explain: by the breaking up of the first form of the white, the colliquament is produced; and from the consumption of this colliquament, follows the form of the blood, in the same way precisely as food is converted into the substance of the thing fed.

It is thus, then, that the chick is said to be made out of the egg, as it were by a contrary; for in the nutrition and growth of the chick in the egg, white and yelk are equally broken up and consumed, and finally the whole substance of the egg. It is clear, therefore, that the chick is formed from the egg, as it were by a contrary, namely the aliment, and as if by an abstraction, and from a non-entity. For the first particle of the chick, viz.: the blood or punctum saliens, is constituted out of something which is not blood, and altogether its contrary, the same subject-matter always remaining.

The chick too is made from the egg, as a man is made from a boy. For in the same way, as out of plants seeds arise, and out of seeds, buds, sprouts, stems, flowers, and fruits; so also out of the egg, the seed of the hen is produced, the dilatation of the cicatricula and the colliquament, the blood and the heart, as the first particle of the fœtus or fruit; and all this, in the same way as the day from the night, the summer from the spring, a man from a boy—one follows or comes after the other. So that, in the same way as fruits arise after flowers on the same stem, so likewise is the colliquament formed after the egg, the blood after this, as from the primogeneous humour, the chick after the blood, and out of it, as the whole out of a part; in the same way, as by Epicharmus’s exaggeration, out of calumnies comes cursing, and out of cursing fighting. For the blood first begins its existence with the punctum saliens, and at the same time, seems to be as well a part of the chick, and a kind of efficient or instrument of its generation, inseparable, as Fabricius thinks, from the agent. But how the egg may be called the efficient and instrument of generation, has partly been explained already, and will be illustrated more copiously by what we shall presently say.

So much has been fully established in our history, that the punctum pulsans and the blood, in the course of their growth, attach round themselves the rest of the body, and all the other members of the chick, just as the yelk in the uterus, after being evolved from the ovary, surrounds itself with the white; and this not without concoction and nutrition. Now the common instrument of all vegetative operations, is, in the opinion of all men, an internal heat or calidum innatum, or a spirit diffused through the whole, and in that spirit a soul or faculty of a soul. The egg, therefore, beyond all doubt, has its own operative soul, which is all in the whole, and all in each individual part, and contains within itself a spirit or animal heat, the immediate instrument of that soul. To one who should ask then, how the chick is made from the egg, we answer: after all the ways recited by Aristotle, and devised by others, in which it is possible for one thing to be made from another.

EXERCISE THE FORTY-FOURTH.

Fabricius is mistaken with regard to the matter of the generation of the chick in ovo.

As I proposed to myself at the outset, I continue to follow Fabricius as pointing out the way; and we shall, therefore, consider the three things which he says are to be particularly regarded in the generation of the chick, viz.: the agent, the matter, and the nourishment of the embryo. These must needs be all contained in the egg; he proposes various doubts or questions, and quotes the opinions of the most weighty authorities in regard to them, these opinions being frequently discordant. The first difficulty is in reference to the matter and nourishment of the chick. Hippocrates,[246] Anaxagoras, Alcmaeon, Menander, and the ancient philosophers, all thought that the chick was engendered from the vitellus, and was nourished by the albumen. Aristotle,[247] however, and after him, Pliny,[248] maintained, on the contrary, that the chick was incorporated from the albumen, and nourished by the vitellus. But Fabricius himself, will have it that neither the white nor yelk forms the matter of the chick; he strives to combat both of the preceding opinions, and teaches that the white and the yellow alike do no more than nourish the chick. One of his arguments, amongst a great number of others which I think are less to be acquiesced in, appears to me to have some force. The branches of the umbilical vessels, he says, through which the embryo undoubtedly imbibes its nourishment, are distributed to the albumen and the vitellus alike, and both of these fluids diminish as the chick grows. And it is on this ground, that Fabricius in confirmation of his opinion, says[249]: “Of the bodies constituting the egg, and adapted to forward the generation of the chick, there are only three, the albumen, the vitellus, and the chalazæ; now the albumen and vitellus are the nourishment of the chick; so that the chalazæ alone remain as matter from which it can be produced.”

Nevertheless, that the excellent Fabricius is in error here, we have demonstrated above in our history. For after the chick is already almost perfected, and its head and its eyes are distinctly visible, the chalazæ can readily be found entire, far from the embryo, and pushed from the apices towards the sides: the office of these bodies, as Fabricius himself admits, is that of ligaments, and to preserve the vitellus in its proper position within the albumen. Nor is that true, which Fabricius adds in confirmation of his opinion, namely, that the chalazæ are situated in the direction of the blunt part of the egg. For after even a single day’s incubation, the relative positions of the fluids of the egg are changed, the yelk being drawn upwards, and the chalazæ on either hand removed, as we have already had occasion to say.

He is also mistaken when he speaks of the chalazæ, as proper parts of the egg. The egg consists in fact but of white and yelk; the chalazæ as well as the membranes, are mere appendages of the albumen and vitellus. The chalazæ, in particular, are the extremities of certain membranes, twisted and knotted; they are produced in the same way as a rope is formed by the contortion of its component filaments, and exist for the purpose of more certainly securing the several elements of the egg in their respective places.

Fabricius, therefore, reasons ill when he says, that “the chalazæ are found in the part of the egg where the embryo is produced, wherefore it is engendered from them;” for even on his own showing, this could never take place, he admitting that the chalazæ are extant in either extremity of the egg, whilst the chick never makes its appearance save at the blunt end; in which, moreover, at the first commencement of generation, no chalaza can be seen. Farther, if you examine the matter in a fresh egg, you will find the superior chalaza not immediately under the blunt end or its cavity, but declined somewhat to the side; not to that side, however, where the cavity is extending, but rather to the opposite side. Still farther, from what has preceded, it is obvious that the relative positions of the fluids of the egg are altered immediately that incubation is begun: the eye increased by the colliquament is drawn up towards the cavity in the blunt end of the egg, whence the white and the chalaza are on either hand withdrawn to the side. For the macula or cicatricula which before incubation was situated midway between the two ends, now increased into the eye of the egg, adjoins the cavity in the blunt end, and whilst one of the chalazæ is depressed from the blunt end, the other is raised from the sharp end, in the same way as the poles of a globe are situated when the axis is set obliquely; the greater portion of the albumen, particularly that which is thicker, subsides at the same time, into the sharp end.

Neither is it correct to say, that the chalazæ bear a resemblance in length and configuration to the chick on its first formation, and that the number of their nodules corresponds with the number of the principal parts of the embryo; a statement which gives Fabricius an opportunity of adducing an argument connected with the matter of the chick, based on the similarity of its consistency to that of the chalazæ. But the red mass (which Fabricius regarded as the liver) is neither situated in nor near the chalaza, but in the middle of the clear colliquament; and it is not any rudiment of the liver but of the heart alone. Neither does his view square with the example he quotes of the tadpole, “of which,” he says, “there is nothing to be seen but the head and the tail, that is to say, the head and spine, without a trace of upper or lower extremities.” And he adds, “he who has seen a chalaza, and this kind of conception, in so far as the body is concerned, will believe that in the former, he has already seen the latter.” I, however, have frequently dissected the tadpole, and have found the belly of large size, and containing intestines and liver and heart pulsating; I have also distinguished the head and the eyes. The part which Fabricius takes for the head, is the rounded mass [or entire body] of the tadpole, whence the creature is called ‘gyrinus,’ from its circular form. It has a tail with which it swims, but is without legs. About the epoch of the summer solstice, it loses the tail, when the extremities begin to sprout. Nothing however occurs in the nature of a division of the embryo pullet into the head and spine, which should induce us to regard it as produced from the chalazæ, and in the same manner as the tadpole.

The position and fame of Fabricius, however, a man exceedingly well skilled in anatomy, do not allow me to push this refutation farther. Nor indeed, is there any necessity so to do, seeing that the thing is so clearly exhibited in our history.

Our author concludes, by stating that his opinion is of great antiquity, and was in vogue even in the times of Aristotle.

For my own part, nevertheless, I regard the view of Ulysses Aldrovandus as the older, he maintaining, that the chalazæ are the spermatic fluid of the cock, from which and through which alike the chick is engendered.

Neither notion, however, is founded on fact, but is the popular error of all times: the chalazæ, treads, or treadles, as our English name implies, are still regarded by the country folks as the semen of the cock.

“The treadles (grandines),” says Aldrovandus; “are the spermatic fluid of the cock, because no fertile egg is without them.” But neither is any unprolific egg without these parts, a fact which Aldrovandus was either ignorant of or concealed. Fabricius admits this fact; but though he has denied that the semen of the male penetrates to the uterus or is ever found in the egg, he nevertheless, contends, that the chalazæ alone of all the parts of the egg are impregnated with the prolific power of the egg, and are the repositories of the fecundating influence; and this, with the fact staring him in the face all the while, that there is no perceptible difference between the chalazæ of a prolific and an unprolific egg. And when he admits, that the mere rudiments of eggs in the ovary, as well as the vitelli that are surrounded with albumen, become fecundated through the intercourse of the cock, I conceive that this must have been the cause of the error committed by so distinguished an individual. It was the current opinion, as I have said oftener than once, both among philosophers and physicians, that the matter of the embryo in animal generation, was the geniture, either of the male, or of the female, or resulted from a mixture of the two, and that from this, deposited in the uterus, like a seed in the ground, which produces a plant, the animal was engendered. Aristotle, himself, is not very far from the same view, when he maintains the menstrual blood of the female to be the seed, which the semen of the male coagulates, and so composes the conception.

The error which we have announced, having been admitted by all in former times, as a matter of certainty, it is not to be wondered at, that various erroneous opinions based on each man’s conjecture, should have emanated from it. They, however, are wholly mistaken, who fancy that anything in the shape of a ‘prepared or fit matter’ must necessarily remain in the uterus after intercourse, from which the fœtus is produced, or the first conception is formed, or that anything is immediately fashioned in the uterine cavity that corresponds to the seed of a plant deposited in the bosom of the ground. For it is quite certain, that in the uterus of the fowl, and the same thing is true of the uterus of every other female animal, there is nothing discoverable after intercourse more than there was before it.

It appears, consequently, that Fabricius erred when he said:[250] “In the same way as a viviparous animal is incorporated from a small quantity of seminal matter, whilst the matter which is taken up as food and nourishment is very large; so a small chalaza suffices for the generation of a chick, and the rest of the matter contained in the egg goes to it in the shape of nutriment.” From which it is obvious, that he sought for some such ‘prepared matter’ in the egg, whence the chick should be incorporated; mainly, as it seems, that he might not be found in contradiction with Aristotle’s definition of an egg,[251] viz.: as “that from part of which an animal is engendered; and the remainder of which is food for the thing engendered.” This of Fabricius, therefore, has the look of a valid argument, namely, “Since there are only three parts in the egg,—the albumen, the vitellus, and the chalazæ; and the two former alone supply aliment; it necessarily follows, that the chalazæ alone are the matter from which the chick is constituted.”