Chapter XXXVIII: Introduction (13)

I may here observe, by the way, that in every strong and healthy human fœtus we everywhere discover milk; it is particularly abundant in the thymus gland, though it is also found in the pancreas, through the whole of the mesentery, and in certain lacteal veins and glands, as it seems, situated between the divisions of the mesenteric vessels. Moreover, it can be pressed and indeed sometimes flows spontaneously from the breasts of newly-bom infants, and nurses imagine that this is beneficial to the infant.

And it clearly appears that this fluid, which abounds in the ovum, is no excrementitious matter thrown off by the embryo, nothing like urine or sweat, because its relative quantity is diminished as the period of parturition approaches, when the fœtus is of course larger, and, as it consumes a greater quantity of nutriment, accumulates excrementitious matter more abundantly than it did in the first months of pregnancy. Let it be added, that the bladder is at this time distended with urine. For my own part I have never been able to discover that conduit for the urine, from the bladder to the umbilicus, which anatomists describe under the name of urachus; I have, on the contrary, frequently seen urine escaping by the penis, but never by any urachus, when the bladder was pressed upon with the hand.

So much for what I have observed with reference to the order of the parts in the development of the human fœtus.

In the fourth and last process the parts of the lowest state and order are produced, those, namely, that do not exist as needful to the being or to the maintenance of the individual, but only as defences against external injury, as ornaments, or as weapons of offence.

The outermost part of all, the skin, with its several appendages,--cuticle, hair, wool, feathers, scales, shells, claws, hooves, and other items of the same description, may be regarded as the principal means of defence or protection. And it is well devised by nature, who, indeed, never does aught amiss, that these parts are the last to be engendered, inasmuch as they could never be of use or avail as defences until the animal was born. The common domestic pullet is therefore born covered with down only, not with feathers, like certain other birds which have to be speedily prepared for flight, because it has to seek its food on foot, not on the wing, and by active running about hither and thither. In like manner the young of ducks and geese, which feed swimming, have their feathers and wings perfected at a later period than their feet and legs. It is otherwise with swallows, however, which have to fly sooner than to walk, because they feed on the wing.

The down of the pullet begins to appear after the fourteenth day, the fœtus being already perfect in all its parts. When the feathers first show themselves, they are in the guise of points within the skin, but by and by the feathers project, like plants from the ground, increase in length, become unfolded, invest the whole body, and protect it against the inclemencies of the atmosphere.

Feathers differ from quills in form, use, place of growth, and order of production. The pullet is feathered before it has any quills, for the quill-feathers only grow in the wings and tail, and also spring more deeply, from the very lowest part of the integument, or even from the periosteum, and serve essentially as instruments of motion; the feathers again arise superficially from the skin, and are everywhere present as means of protection.

“Nails, hair, horn, and the like,” says Aristotle,[298] “are engendered from the skin; whence it happens that they change colour with the skin; for the white and black and particoloured are so in consequence of the colour of the skin whence they arise.” In the bird, however, this is not so; for whatever the colour of the feathers, the skin is still never otherwise than of one tint, viz., white. And then the same feather or quill is frequently seen of different and often brilliant colours in different parts for the ornament of the creature.

In the human fœtus the skin and all the parts connected with it are in like manner perfected the last of all. In the earlier periods, consequently, we find neither lips, cheeks, external ears, eyelids, nor nose; and the last part to grow together is the upper lip in the course of the middle line of the body.

Man comes into the world naked and unarmed, as if nature had destined him for a social creature, and ordained him to live under equitable laws and in peace; as if she had desired that he should be guided by reason rather than be driven by force; therefore did she endow him with understanding, and furnish him with hands, that he might himself contrive what was necessary to his clothing and protection. To those animals to which nature has given vast strength, she has also presented weapons in harmony with their powers; to those that are not thus vigorous, she has given ingenuity, cunning, and singular dexterity in avoiding injury.

Ornaments of all kinds, such as tufts, crests, combs, wattles, brilliant plumage, and the like, of which some vain creatures seem not a little proud, to say nothing of such offensive weapons as teeth, horns, spurs, and other implements employed in combat, are more frequently and remarkably conferred upon the male than the female. And it is not uninteresting to remark, that many of these ornaments or weapons are most conspicuous in the male at that epoch when the females come into season, and burn with desire of engendering. And whilst in the young they are still absent, in the aged they also fail as being no longer wanted.

Our common cock, whose pugnacious qualities are well known, so soon as he comes to his strength and is possessed of the faculty of engendering, is distinguished by his spurs, and ornamented with his comb and beautiful feathers, by which he charms his mates to the rites of Venus, and is furnished for the combat with other males, the subject of dispute being no empty or vainglorious matter, but the perpetuation of the stock in this line or in that; as if nature had intended that he who could best defend himself and his, should be preferred to others for the continuance of the kind. And indeed all animals which are better furnished with weapons of offence, and more warlike than others, fall out and fight, either in defence of their young, of their nests or dens, or of their prey; but more than all for the possession of their females. Once vanquished, they yield up possession of these, lay aside their strut and haughty demeanour, and, crest-fallen and submissive, they seem to consume with grief; the victor, on the contrary, who has gained possession of the females by his prowess, exults and boastfully proclaims the glory of his conquest.

Nor is this ornamenting anything adventitious and for a season only; it is a lasting and special gift of nature, who has not been studious to deck out animals, and especially birds only, but has also thrown an infinite variety of beautiful dyes over the lowly and insensate herbs and flowers.

EXERCISE THE FIFTY-SEVENTH.

_Of certain paradoxes and problems to be considered in connexion with this subject._

Thus far have we spoken of the order of generation, whereby the differences between those creatures that are engendered by metamorphosis and those that are developed by epigenesis, as well as between those that are said to proceed from a worm and those that arise from an egg, have been made to appear. The latter are partly incorporated from a prepared matter, and are nourished and increased from a certain remaining matter; the former are incorporated from the whole of the matter present; the latter grow and are formed simultaneously, and after their birth continue to wax in size and finally attain maturity; the former increase at once, and from a grub or caterpillar grow into an aurelia, and are then produced, consummately formed, as butterflies, moths, and the like. Wherefore Aristotle, as Fabricius[299] observes: “As he assigns a sort of twofold nature to the egg, and a twofold egg in this kind, so does he assert a twofold action and a twofold animal engendered. For,” he proceeds, “from the first eggs, which are the primordia of generation, a worm is constantly produced; viz.: from the eggs of flies, ants, bees, silkworms, &c., in which some fluid is contained, and from the whole of which fluid the worm is engendered; but from the second eggs, formed by the worms themselves, butterflies are engendered and disclosed, viz.: flying animals contained in a shell, or follicle, or egg, which shell giving way the winged creature escapes; precisely as Aristotle[300] has it where he speaks of the egg of the locust.” Finally, whilst the higher animals produced from eggs are perfected by a succession of parts, the lower creatures that arise in this way, or that are formed by metamorphosis, are produced at one effort, as it were, and entire. And in the same way are engendered both those creatures that are said to arise spontaneously, by chance or accident, and derive their first matter or take their origin from putrefaction, filth, excrement, dew, or the parts of plants and animals, as well as those that arise congenerately from the semen of animals. Because this is common to all living creatures, viz.: that they derive their origin either from semen or eggs, whether this semen have proceeded from others of the same kind, or have come by chance or something else. For what sometimes happens in art occasionally occurs in nature also; those things, namely, take place by chance or accident which otherwise are brought about by art. Of this Aristotle[301] quotes health as an illustration. And the thing is not different as respects the generation, in so far as it is from seed, of certain animals: their semina are either present by accident, or they proceed from an univocal agent of the same kind. For even in fortuitous semina there is an inherent motive principle of generation, which procreates from itself and of itself; and this is the same as that which is found in the semina of congenerative animals,--a power, to wit, of forming a living creature. But of this matter we shall have more to say shortly.

From what has just been said, however, several paradoxes present themselves for consideration. For when we see the cicatricula enlarging in the egg, the colliquament concocted and prepared, and a variety of other particulars all tending, not without foresight, to the development of the embryo, before the first rudiment or the merest particle of this is conspicuous, what should hinder us from believing that the calidum innatum and the vegetative soul of the chick are in existence before the chick itself? For what is competent to produce the effects and acts of life, except their efficient cause and principle, heat, namely, and the faculty of the vegetative soul? Therefore it would seem that the soul was not the act of the organic body possessing life in potentia; for we regard the chick with its appropriate form as the consequence of such an act. But where can we suppose the form and vital principle of the chick to inhere save in the chick itself? unless indeed we admitted a separation of forms and conceded a certain metamorphosis.

Now this appears most obviously where the same animal lives, as Aristotle has it, by or under a succession of forms, for example, a caterpillar, a chrysalis, a butterfly. For it is of necessity the same efficient, nutrient, and conservative principle that possesses each of these, although under different forms; unless we allow that there is one vital principle in the youth, another in the man, a third in the aged individual, or maintain that the forms of the grub and caterpillar are the same as those of the silkworm and butterfly. Aristotle has entered very fully into this subject, and we shall ourselves have more to say on it immediately.

It appears further paradoxical to maintain that the blood is produced, and moves to and fro, and is imbued with vital spirits, before any sanguiferous or locomotive organs are in existence. Neither is it less new and unheard-of to assert, that sensation and motion belong to the fœtus before the brain is formed; for the fœtus moves, contracting and unfolding itself, when there is nothing more than a little limpid water in the place of the brain.

Moreover, the body is nourished and increases before the organs appropriated to digestion, viz. the stomach and abdominal viscera, are formed. Sanguification, too, which is entitled the second digestion, is perfect before the first, or chylification, which takes place in the stomach, is begun. The excrementitious products of the first and second digestions, namely, excrement in the intestines, urine and bile in the urinary and gall bladder, are contemporaneous with the existence of the concocting organs themselves. Lastly, not only is there a soul or vital principle present in the vegetative part, but even before this there is inherent mind, foresight, and understanding, which from the very commencement to the being and perfect formation of the chick, dispose and order and take up all things requisite, moulding them in the new being, with consummate art, into the form and likeness of its parents.

In reference to this subject of family likeness, we may be permitted to inquire as to the reason why the offspring should at one time bear a stronger resemblance to the father, at another to the mother, and, at a third, to progenitors, both maternal and paternal, further removed? particularly in cases where at one bout, and at the same moment, several ova are fecundated. And this too is a remarkable fact, that virtues and vices, marks and moles, and even particular dispositions to disease are transmitted by parents to their offspring; and that while some inherit in this way, all do not. Among our poultry some are courageous, and pugnaciously inclined, and will sooner die than yield and flee from an adversary; their descendants, once or twice removed, however, unless they have come of equally well-bred parents, gradually lose this quality; according to the adage, “the brave are begotten by the brave.” In various other species of animals, and particularly in the human family, a certain nobility of race is observed; numerous qualities, in fact, both of mind and body, are derived by hereditary descent.

I have frequently wondered how it should happen that the offspring, mixed in so many particulars of its structure or constitution, with the stamp of both parents so obviously upon it, in so many parts, should still escape all mixture in the organs of generation; that it should so uniformly prove either male or female, so very rarely an hermaphrodite.

Lastly, many things are present before they appear, and some are begun among the very first which are completed among the very last, such as the eyes, the organs of generation, and the beak.

Several doubts and difficulties have thence arisen as to the principality and relative dignity of the several members, in which they who are fond of such things have displayed their ingenuity. Among the number: whether the heart gives life and virtue to the blood; or, rather, the blood to the heart. Whether the blood be extant for the sake of the body as matter, nourishment, and instrument; or, on the contrary, the body and its parts are the cause of the blood, and constituted for the sake of the vital principle which especially inheres in it. In like manner, whether the auricles or the ventricles of the heart are the chief, the auricles being the first to live and pulsate, the last to die. Further, whether the left ventricle, which in man is of greater length, and is also surrounded with thicker and more fleshy walls, and is regarded as the source of the spirits, be hotter, more spirituous, excitable, and excellent, than the right, which contains a larger quantity of blood, and is the last to become unstrung by death; in which the blood of the dying accumulates, congeals, and is deprived of life and spirit; to which, moreover, as to a fountain head, the first umbilical veins bring their blood, and from which they themselves derive their origin.

So much appears from careful observation of the order observed in the production of the parts, and certain other points that follow as deductions from these, and do not a little militate against the commonly received physiological doctrines, viz.: since it is manifest that sensation and motion exist before the brain, all sensation and motion do not proceed from the brain; from our history it is clearly ascertained that sense and movement inhere in the very first drop of blood produced in the egg, before there is a vestige of the body. The first scaffolding or rudiment of the body, too, which we have said is merely mucilaginous, before any of the extremities are visible, and when the brain is nothing more than a limpid fluid, if lightly pricked, will move obscurely, will contract and twist itself like a worm or caterpillar, so that it is very evidently possessed of sensation.

There are yet other arguments deduced from sense and motion whence we should infer that the brain was not so much the first principle of the body, in the way the medical writers maintain, as the heart, agreeably to Aristotle’s view.

The motions and actions which physicians style _natural_, because they take place involuntarily, and we can neither prevent nor moderate, accelerate nor retard them by our will, and they therefore do not depend on the brain, still do not occur entirely without causing sensation, but proclaim themselves subject to sense, inasmuch as they are aroused, called forth, and changed thereby. When the heart, for example, is affected with palpitation, tremor, lipothymia, syncope, and with great variety in the extent, rapidity, and order or rhythm of its pulsations, we do not hesitate to ascribe these to morbific causes implicating, deranging its sensation. For whatever by its divers movements strives against irritations and troubles must necessarily be endowed with sensation.

The stomach and bowels, disturbed by the presence of vitiated humours, are affected with ructus, flatus, vomiting, and diarrhœa; and as it lies not in our power either to provoke or to restrain their motions, neither are we aware of any sensation dependent on the brain which should arouse the parts in question to motions of the kind.

It is truly wonderful to observe the effect of taking a solution of antimony, which we neither distinguish by the taste, nor find any inconvenience from, whether in the swallowing or the rejection. Nevertheless there is a certain discriminating sense in the stomach which distinguishes what is hurtful from what is useful, and by which vomiting is induced.

Nay, the flesh itself readily distinguishes a poisoned wound from one that is not poisoned, and on receipt of the former contracts and condenses itself, whereby phlegmonous tumours are produced, as we find in connexion with the stings of bees, gnats, and spiders.

I have myself, for experiment’s sake, occasionally pricked my hand with a clean needle, and then having rubbed the same needle on the teeth of a spider, I have pricked my hand in another place. I could not by my simple sensation perceive any difference between the two punctures; nevertheless there was a capacity in the skin to distinguish the one from the other; for the part pricked with the envenomed needle immediately contracted into a tubercle, and by and by became red, and hot, and inflamed, as if it collected and girded itself up for a contest with the poison for its overthrow.

The sensations which accompany affections of the uterus, such as twisting, decubitus, prolapse, ascent, suffocation, &c., and other inconveniences and irritations, do not depend on the brain or on common sensation; yet neither are these to be presumed as happening without all consciousness. For that which is wholly without sense is not seen to be irritated by any means, neither can it be stimulated to motion or action of any kind. Nor have we any other means of distinguishing between an animate and sentient thing and one that is dead and senseless than the motion excited by some other irritating cause or thing, which as it incessantly follows, so does it also argue sensation.

But we shall have an opportunity of speaking farther of this matter when we discuss the actions and uses of the brain. Respect for our predecessors and for antiquity at large inclines us to defend their conclusions to the extent that love of truth will allow. Nor do I think it becoming in us to neglect and make little of their labours and conclusions who bore the torch that has lighted us to the shrine of philosophy. I am, therefore, of opinion that we should conclude in this way: we have consciousness in ourselves of five principal senses, by which we judge of external objects; but we do not feel with the same sense by means of which we are conscious that we feel--seeing with our eyes, we still do not know by them that we see, but by another sense or sensitive organ, namely, the internal common sensation or common sensorium, by which we examine those things that reach us through each of the external sensoria, and distinguish that which is white from that which is sweet or hard. Now this sensorium commune to which the species or impressions of all the external instruments of sensation are referred, is obviously the brain, which along with its nerves and the external organs annexed, is held and esteemed to be the adequate instrument of sensation. And this brain is like a sensitive root to which a variety of fibres tend, one of which sees, another hears, a third touches, and a fourth and a fifth smell and taste.

But as there are some actions and motions the government or direction of which is not dependent on the brain, and which are therefore called _natural_, so also is it to be concluded that there is a certain sense or form of touch which is not referred to the common sensorium, nor in any way communicated to the brain, so that we do not perceive by this sense that we feel; but, as happens to those who are deranged in mind, or who are agitated to such a degree by violent passion that they feel no pain, and pay no regard to the impressions made on their senses, so must we believe it to be with this sense, which we therefore distinguish from the proper animal sense. Now such a sense do we observe in zoophytes or plant-animals, in sponges, the sensitive plant, &c.

Wherefore, as many animals are endowed with both sense and motion without having a common sensorium or brain, such as earthworms, caterpillars of various kinds, chrysalides, &c., so also do certain natural actions take place in the embryo and even in ourselves without the agency of the brain, and a certain sensation takes place without consciousness. And as medical writers teach that the natural differ from the animal actions, so by parity of reason does the natural sense of touch differ from the animal sense of touch,--it constitutes, in a word, another species of touch; and whilst the one is communicated to the common sensorium, the other is not so communicated.

Further, it is one thing for a muscle to be contracted and moved, and another for it by regulated contractions and relaxations to perform any movement, such as progression or prehension. The muscles or organs of motion, when affected with spasms or convulsions from an irritating cause, are assuredly moved no otherwise than the decapitated cock or hen, which is agitated with many convulsive movements of its legs and wings, but all confused and without a purpose, because the controlling power of the brain has been taken away:--common sensation has disappeared, under the controlling influence of which these motions were formerly coordinated to progression by walking or to flight.

We therefore conceive the fact to be that all the natural motions proceed from the power of the heart, and depend on it; the spontaneous motions, however, and those that complete any motion which physicians entitle an animal motion, cannot be performed without the controlling influence of the brain and common sensation. For inasmuch as by this common sensation we are conscious of our perceptions, so also are we conscious that we move, and this whether the motion be regular or otherwise.

We have an excellent example of both of these kinds of motion in respiration. For the lungs, like the heart, are continually carried upwards and downwards by a natural movement, and are excited by any irritation to coughing and more frequent action; but they cannot form and regulate the voice, nor can singing be executed, without the assistance, and in some sort the command, of the sensorium commune.

But these matters will be more fully handled when we come to speak of the actions and uses of the brain, and to consider the vital principle or soul. So much we have thought fit to say by the way, that we might show the respect in which we hold our illustrious teachers, and our anxiety to carry them along with us in our labours.

EXERCISE THE FIFTY-EIGHTH.

_Of the nutrition of the chick in ovo._

That the authority of the ancients is not to be rashly thrown off appears in this: it was formerly current doctrine, though many at the present day, Fabricius[302] among the number, reject it as a delusion and a foolish idea, that the embryo sucked in its mother’s womb. This idea nevertheless had Democritus, Epicurus, and Hippocrates for its supporters; and the father of physic contends for it on two principal grounds: “Unless the fœtus sucked,” he says,[303] “how should excrements be formed? or how should it know how to suck immediately after it is born?”

Now, whilst in other instances it is customary to swear by the bare statement of this ancient and most distinguished writer, his _ipse dixit_ (ἀυτὸς ἔφη) sufficing, because he here makes an assertion contrary to the commonly received opinion, Fabricius not only denies the statement, but spurns the arguments in support of his conclusion. We, however, leave it to the judgment of skilful anatomists and learned physicians to say whether our observations on the generation of animals do not proclaim this opinion of Hippocrates to be not merely probable, but even necessary.

All admit that the fœtus in utero swims in the midst of an abundance of a watery fluid, which in our history of the egg we have spoken of as the colliquament, this fluid modern authorities regard as the sweat and excrement of the fœtus, and ascribe as its principal use the protection of the uterus against injury from the fœtus during any violent motion of the mother in running or leaping; and, on the other hand, the defence of the fœtus from injury through contact with neighbouring bones, or an external cause, particularly during the period when its limbs are still delicate and weak.

Fabricius[304] ascribes additional uses to this fluid, viz. “that it may moisten and lubricate all the parts around, and dispose the neck of the uterus to facile and speedy dilatation to the utmost extent; and all this is not less assisted by that thick, white, excrementitious matter of the third digestion, neglected by the ancients, which is unctuous and oily, and farther prevents the sweat, which may occasionally be secreted sharp and salt in quality, from excoriating the tender body of the fœtus.”

I readily acknowledge all the uses indicated, viz. that the tender fœtus may be secure against all sudden and violent movements of the mother, that he may ride safe in the “bat’s wings,” as they are called, and, surrounded with an abundance of water, that he may escape coming into contact with his mother’s sides, being restrained by the retinacular fluid on either hand: this circumambient fluid must certainly protect the body which floats in its middle from all external injury. But, as in many other instances, my observations compel me here to be of a different opinion from Fabricius. In the first place, I am by no means satisfied that this fluid is the sweat of the fœtus. And then I do not believe that the fluid serves those important purposes in parturition which he indicates; and much less that it is ever so sharp and saline that an unctuous covering was requisite to protect the fœtus from its erosive effects, particularly in those cases where there is already a thick covering of wool, or hair, or feathers. The fluid, in fact, has a pleasant taste, like that of watery milk, so that almost all viviparous animals lap it up, and cleanse their new-born progeny by licking them with their tongues, greedily swallowing the fluid, though none of them was ever seen to touch any of the excrements of their young.

Fabricius spoke of this fluid as saline and acrimonious, because he believed it to be sweat. But what inconvenience, I beseech you, were sweat to the chick, already covered with its feathers?--if indeed any one ever saw a chicken sweat. Nor do I think he could have said that the use of this fluid in the egg was, by its moistening and lubrifying qualities, to facilitate the birth of the chick; for the drier and older the shell of the egg, the more friable and fragile it becomes. Finally, were it the sweat of the embryo, or fœtus, it ought to be most abundant nearest the period of parturition: the larger the fœtus and the more food it consumes, the more sweat must it necessarily secrete. But shortly before the exclusion of the chick from the egg, namely, about the nineteenth or twentieth day, there is none of the fluid to be seen, because as the chick grows it is gradually taken up; so that if the thing be rightly viewed, the fluid in question ought rather to be regarded as nutriment than as excrement, particularly as he has said that the chick in the egg breathes, and lets its chirping be heard, which it certainly would not do were it surrounded with water.

But all experienced obstetricians know that the watery fluid of the secundines is of no great use either in lubricating the parts or in facilitating the progress of parturition in the way Fabricius would have it. For the parts surrounding the vulva are relaxed of themselves, and by a kind of proper maturity at the full time, without any assistance from the uterine waters; and particularly those that offer the greatest obstacles to the advance of the fœtus, namely, the ossa pubis and the os coccygis, to which the attention of the midwife is especially directed in assisting the woman in labour. For midwives are much less studious to anoint the soft parts with any emollient salves, lest they tear, than careful to pull the os coccygis outwards, a business in which, if the fingers do not suffice, they have recourse to the uterine speculum, applied by the hand of the experienced surgeon, an instrument having three sides or branches, one of which bearing on the os coccygis, the other two on the ossa pubis, the business of distension is effected by force. For the head of the child that is about to be born, when it makes the turn, and is forced downwards, relaxes and opens the os uteri; but coming down he will stick fast, and scarcely be brought forth if he chance to abut upon the point of the os coccygis, and immediately the case is one not without danger both to the child and mother. But nature’s intention was obviously to relax and soften all the parts concerned; and the attendant knows that when the uterine orifice is discovered in a soft and lax condition, by the finger introduced, it is an infallible sign that the delivery is at hand even though the waters have not broken. Indeed--and I do not speak without experience--if anything remains in the uterus for expulsion, either after delivery or at any other time, and the uterus make efforts to get rid of it, the orifice both descends lower and is found soft and relaxed. If the uterine orifice recedes, and is found somewhat hard after delivery, it is a sign of the woman’s restoration to health.

Taught by like experience, I assert that the ossa pubis frequently become loosened during labour, their cartilaginous connexion being softened, and the whole hypogastric region enlarged in the most miraculous manner, not, however, by any pouring out of watery fluids, but spontaneously, as ripe fruit gapes that the included seed may find an exit. The degree in which the coccyx may impede delivery, however, is apparent among quadrupeds having tails, which can neither bring forth, nor even discharge the excrement from their bowels, unless the tail be raised; if you but depress the tail with your hand, you prevent the exit of the dung.

Moreover, the most natural labour of all is held to be that in which the fœtus and afterbirth, the waters inclusive, or the ovum, is expelled entire. Now if the membranes have not given way, and the waters have not escaped, it comes to pass that the surrounding parts are more than usually distended and dilated by the labour pains, in consequence, to wit, of the entire and tense state of the membranes, by which it happens that the fœtus is produced more speedily, and with a less amount of effort, although with more suffering to the mother. In cases of this kind we have known women who were suffering much in their travail in consequence of the too great distension, immensely relieved by the rupture of the membranes and the sudden escape of the waters, the laceration being effected either with the nails of the midwife or the use of a pair of forceps.

Experienced midwives are farther aware that if the waters come away before the orifice of the uterus is duly dilated, the woman is apt to have a lingering time and a more difficult delivery, contrary to Fabricius’s notion of the waters having such paramount influence in softening and lubricating the parts.

Moreover, that the fluid which we have called colliquament is not the sweat of the fœtus is made obvious, both from the history of the egg and of the uterogestation of other animals: it is present before the fœtus is formed in any way, before there is a trace of it to be seen; and whilst it is still extremely small and entirely gelatinous, the quantity of water present is very great, so that it seems plainly impossible that so small a body should produce such a mass of excrementitious fluid.

It happens besides that the ramifications of the umbilical veins are distributed over and terminate upon the membrane which incloses this fluid, precisely as on the membranes of the albumen and yelk of the egg, a circumstance from which, and the thing being viewed as it is in fact, it appears to be clearly proclaimed that this fluid is rather to be regarded as food than as excrement.

To me, therefore, the opinion of Hippocrates appears more probable than that of Fabricius and other anatomists, who look on this liquid as sweat, and believe that it must prove detrimental to the fœtus. I am disposed, I say, to believe that the fluid with which the fœtus is surrounded may serve it for nourishment; that the thinner and purer portions of it, taken up by the umbilical veins, may serve for the constitution and increase of the first formed parts of the embryo; and that from the remainder or the milk, taken into the mouth by suction, passed on to the stomach by the act of deglutition, and there digested or chylified, and finally absorbed by the mesenteric veins, the new being continues to grow and be nourished. I am the more disposed to take this view from certain not impertinent arguments, which I shall proceed to state.

As soon as the embryo acquires a certain degree of perfection it moves its extremities, and begins to prove the actions of the organs destined to locomotion. Now I have seen the chick in ovo, surrounded with liquid, opening its mouth, and any fluid that thus gained access to the fauces must needs have been swallowed; for it is certain that whatever passes the root of the tongue and gains the top of the œsophagus, cannot be rejected by any animal with a less effort than that of vomiting. This fact is acted upon every day by veterinary practitioners, who in administering medicated drinks and pills or boluses to cattle, seize the tongue, and having put the article upon its root beyond the protuberant part, the animal cannot do otherwise than swallow it. And if we make the experiment ourselves, we find that a pill carried between the finger and thumb as far as the root of the tongue and there dropped, immediately the action of deglutition is excited, and unless vomiting be produced the pill is taken down. If the embryo swimming in the fluid in question, then, do but open his mouth, it is absolutely necessary that the fluid must reach the fauces; and if the creature then move other muscles, wherefore should we not believe that he also uses his throat in its appropriate office and swallows the fluid?

It is further quite certain that in the crop of the chick,--and the same thing occurs in reference to the stomach of other embryos--there is a certain matter having a colour, taste, and consistence, very similar to that of the liquid mentioned, and some of it in the stomach digested to a certain extent, like coagulated milk; and further, whilst we discover a kind of chyle in the upper intestines, we find the lower bowels full of stercoraceous excrements. In like manner we perceive the large intestines of the fœtuses of viviparous animals to contain excrements of the same description as those that distend them when they feed on milk. In the sheep and other bisulcated animals we even find scybala.

Towards the seventeenth day we find dung very obviously near the anus of the chick; and shortly before the extrusion I have seen the same matter expelled and contained within the membranes. Volcher Coiter, a careful and experienced dissector, states that he has observed the same thing.

Wherefore should we doubt, then, that the fœtus in utero sucks, and that chylopoiesis goes on in its stomach, when we find present both the principles and the recrementitious products of digestion?

And then, when we find the bladder both of the bile and the urine full of those excrements of the second digestion, wherefore should we not conclude that the first digestion, or chylopoiesis, has preceded?

The embryo, therefore seeks for and sucks in nourishment by the mouth; and you will readily believe that he does so if you rip him from his mother’s womb and instantly put a finger in his mouth; which Hippocrates thinks he would not seize had he not previously sucked whilst in the womb. For we are accustomed to see young infants trying various motions, making experiments, as it were, approaching everything, moving their limbs, attempting to walk, and uttering sounds, acts all of which when taught by repeated experience, they afterwards come to execute with readiness and precision. But the fœtus so soon as it is born, aye, before it is born, will suck; doubtless as it had done in the uterus long before. For I have found by experience that the child delayed in the birth, and before it has cried or breathed, will seize and suck a finger put into its mouth. A new-born infant, indeed, is more expert at sucking than an adult, or than he is himself if he have but lost the habit for a few days. For the infant does not suck by squeezing the nipple with his lips as we should, and by suction in the common acceptation; he rather seems as if he would swallow the nipple, drawing it wholly into his throat, and with the aid of his tongue and palate, and chewing, as it were, he milks his mother with more art and dexterity than an adult could practise. He therefore appears to have learned that by long custom, and before he saw the light, which we know full well he unlearns by a very brief discontinuance.

These and other observations of the same kind make it extremely probable that the chick in ovo is nourished in a twofold manner, namely, by the umbilical and by the mesenteric veins. By the former he imbibes a nourishment that is well nigh perfectly prepared, whence the first-formed parts are engendered and augmented; by the latter he receives chyle for the structure and growth of the other remaining parts.

But the reason is perhaps obscure why the same agent should perform the work of nutrition by means of the same matter in a variety of ways, since nature does nothing in vain. We shall therefore endeavour to explain this.

What is taken up by the umbilical veins is the purer and more limpid part; and the rest of the colliquament in which the fœtus swims is like crude milk, or milk deprived of its purer portion. The purer part does not require any of that ulterior concoction of which the remainder stands in need; and to undergo which it is taken into the stomach, where it is transmuted into chyle. Similar to this is the crude and watery milk which is found in the breasts immediately after parturition. The liquefied albumen of the egg, and the crude or watery milk of the mammæ seem to have in all respects the same colour, taste, and consistence. For the first flow of milk is serous and watery, and women are wont to express water from their breasts before the milk comes white, concocted, and perfect.

Just as the colliquament found in the crop of the chick is a kind of crude milk, whilst the same fluid discovered in the stomach is concocted, white, and curdled; so in viviparous animals, before the milk is concocted in the mammæ, a kind of dew and colliquament makes its appearance there, and the colliquament only puts on the semblance of milk after it has undergone concoction in the stomach. And so it happens, in Aristotle’s opinion, that the first and most essential parts are formed out of the purer and thinner portion of the colliquament, and are increased by the remaining more indifferent portion after it has undergone elaboration by a new digestion in the stomach. In the same way are the other less important parts developed and maintained. Thus has nature, like a fond and indulgent mother, been sedulous rather to provide superfluity, than to suffer any scarcity of things necessary. Or it might be said to be in conformity with reason to suppose that the fœtus, now grown more perfect, should also be nourished in a more perfect manner, by the mouth, to wit, and by a more perfect kind of aliment, rendered purer by having undergone the two antecedent digestions and been thereby freed from the two kinds of excrementitious matter. In the beginning and early stages, nourished by the ramifications of the umbilical veins, it leads in some sort the life of a plant; the body is then crude, white, and imperfect; like plants, too, it is motionless and impassive. As soon, however, as it begins by the mouth to partake of the same aliment farther elaborated, as if feeling a diviner influence, boasting a higher grade of vegetative existence, the gelatinous mass of the body is changed into flesh, the organs of motion are distinguished, the spirits are perfected, and motion begins; nor is it any longer nourished like a vegetable, by the roots, but, living the life of an animal, it is supported by the mouth.

EXERCISE THE FIFTY-NINTH.

_Of the uses of the entire egg._

Having now gone through the several changes and processes which must take place in the hen’s egg, in order that it may produce a chick, Fabricius proceeds to consider the uses of the egg at large, and of its various parts; nor does he restrict himself to the hen’s egg, but condescends upon eggs in general. Among other things he inquires: wherefore some eggs are heterogeneous and composed of different elements; and others are homogeneous and similar? such as the eggs of insects, and those creatures that are engendered from the whole egg, viz. by metamorphosis, and are not engendered from one part of the egg, and nourished by another part.

I have no purpose myself of entering on a general consideration of eggs of all kinds and descriptions; I have not yet given the history of all, but only of the hen’s egg; so that I shall here limit myself to a survey of the uses of the common hen’s egg, keeping in view the end of all its actions, which is nothing less than the production and completion of a new being, as Fabricius has well and truly said.[305]

Among the points having reference to the whole egg, Fabricius speaks of the form, dimensions, and number of eggs. “The figure of the egg is round,” he says,[306] “in order that the mass of the chick may be stowed in the smallest possible space; for the same cause that God made the world round, namely, that it might embrace all things; and it is from this, as Galen conceives, that this figure is always felt to be most agreeable and consonant to nature. Further, as it has no angles exposed to injury from without, it is, therefore, the safest figure, and the one best adapted to effect the exclusion of the chick.” It had been well after such a preface to have assigned satisfactory causes why hen’s eggs are not spherical, like the eggs of fishes, worms and frogs, but oblong and pointed; to have shown what there is in them which hinders the presumed perfection of figure. Now to me the form of the egg has never appeared to have aught to do with the engenderment of the chick, but to be a mere accident; and to this conclusion I come the rather when I see such diversities in the shape of the eggs of different hens. They vary, in short, in conformity with the variety that obtains among the uteri of different fowls, in which, as in moulds, they receive their form.

Aristotle,[307] indeed, says that the longer-shaped eggs produce females, the rounder males. I have not made any experiments upon this point myself. But Pliny[308] asserts, in opposition to Aristotle, that the rounder eggs produce females, the others males. Now were there any certainty in such statements, either in one way or the other, some hens would always produce males, others always females, inasmuch as the eggs of the same hen are in many instances always of one figure, namely, either much rounded or acutely pointed. Horace[309] thought that the oblong eggs, as being the more perfect and better concocted, and therefore the better flavoured, produced males.

I willingly pass by the reasons alleged by Fabricius for the form of eggs, as being all irrelevant.

The size of an egg appears to bear a proportion to the size of the fœtus produced from it; large hens, too, certainly lay large eggs. The crocodile, however, lays eggs the size of those of the goose; nor does any animal attain to larger dimensions from a smaller beginning. It would seem, too, that the size of the egg and the quantity of matter it contained had some connexion with its fecundity, inasmuch as the very small eggs called centenines are all barren.

The number of eggs serves the same end as abundance of conceptions among viviparous animals--they secure the perpetuity of the species. Nature appears to have been particularly careful in providing a numerous offspring to those animals which, by reason of their pusillanimity or bodily weakness, hardly defend themselves against the attacks of others; she has counterbalanced the shortness of their own lives by the number of their progeny. “Nature,” says Pliny,[310] “has made the timid tribes among birds more fruitful than the bold ones.” All generation as it is instituted by nature for the sake of perpetuating species, so does it occur more frequently among those that are shorter-lived and more obnoxious to external injury lest their race should fail. Birds that are of stronger make, that prey upon other creatures, and therefore live more securely and for longer terms scarcely lay more than two eggs once a year. Pigeons, turtle and ring-doves, that lay but a couple of eggs, make up for the smallness of the number by the frequency of laying, for they will produce young as often as ten times in the course of a year. They therefore engender greatly although they do not produce many at a time.

EXERCISE THE SIXTIETH.

_Of the uses of the yelk and albumen._

“An egg,” says Fabricius,[311] “properly so called, is composed of many parts, because it is the organ of the engenderer, and Galen everywhere insists on the constitution of an organ as implying multiplicity of parts.” But this view leads us to ask whether every egg must not be heterogeneous, seeing that every egg is organic? And every egg, indeed, even that of the fish and insect, appears to be composed of several different parts,--membranes, coverings, defences; nor is the included matter by any means without diversity of constitution in different parts.

Fabricius agrees farther, and correctly, with Galen, when he says:[312] “Some parts of the egg are the chief instruments of the actions that take place in it, others may be styled necessary,--without them no actions could take place; others exist that the action which takes place may be better performed; others, in fine, are destined for the safety and preservation of all of these.” But he is mistaken when he says: “If we speak of the prime action, which is the generation of the chick, the chief cause of this is the semen and the chalazæ, these two being the prime cause of the generation of the chick, the semen being the efficient cause, the chalaza the matter only.” Now according to the opinion of Aristotle, it must be allowed that that which generates is included in the egg; but Fabricius denies that the semen of the cock is contained in the egg.

Nor does he wander less wide of the mark when he speaks of the chalazæ as the matter from which, by the influence of the semen galli, the chick is incorporated. For the chick is not produced either from one or the other, nor yet from both of the chalazæ, as we have shown in our history. Neither is the generation of the chick effected by metamorphosis, nor by any new form assumed and division effected in the chalazæ, but by epigenesis, in the manner already explained. Nor are the chalazæ especially fecundated by the semen of the male bird, but the cicatricula rather, or the part which we have called the eye of the egg, from which, when it enlarges, the colliquament is produced, in and from which, subsequently, the blood, the veins, and the pulsating vesicles proceed, after which the whole body is gradually formed. Moreover, on his own admission, the semen of the cock never enters the uterus of the hen, and yet it fecundates not only the eggs that are already formed, but others that are yet to be produced.

Fabricius refers the albumen and vitellus to the second action of the egg, which is the nutrition and growth of the chick. “The vitellus and albumen,” he says,[313] “are in quantity commensurate with the perfect performance of this action, and with the due development and growth of the chick. The shell and membranes are therefore the safety of the whole of the egg as well as the security of its action. But the veins and arteries which carry nourishment are organs without which the action of the egg, in other words, the growth and nutrition of the chick, would not take place.” It is uncertain, however, whether the umbilical vessels of the embryo or the veins and arteries of the mother, whence the egg is increased, are here to be understood. For a like reason the uterus and incubation ought to be referred to this last class of actions.

We have to do, then, with the two fluids of the egg, the albumen and the vitellus; for these, before all the other parts, are formed for the use of the embryo, and in them is the second action of the egg especially conspicuous.