EXERCISE THE FIFTY-FIRST.
Of the order of generation; and, first, of the primary genital particle.
It will be our business, by and by, when we come to treat of the matter in especial, to show what happens to the female from a fruitful embrace; what it is that remains with her after this, and which we have still spoken of under the name of contagion, by which, as by a kind of infection, she conceives, and an embryo subsequently begins to grow of its own accord. Meantime, we shall discourse of those things that manifestly appear in connexion with the organs of generation which seem most worthy of particular comment.
And first, since it appears certain that the chick is produced by epigenesis, or addition of the parts that successively arise, we shall inquire what part is formed first, before any of the rest appear, and what may be observed of this and its particular mode of generation.
What Aristotle[271] says of the generation of the more perfect animals, is confirmed and made manifest by all that passes in the egg, viz.: that all the parts are not formed at once and together, but in succession, one after another; and that there first exists a particular genital particle, in virtue of which, as from a beginning, all the other parts proceed. As in the seeds of plants, in beans and acorns, to quote particular instances, we see the gemmula or apex, protruding, the commencement of the entire prospective herb or tree. “And this particle is like a child emancipated, placed independently, a principle existing of itself, from whence the series of members is subsequently thrown out, and to which belongs all that is to conduce to the perfection of the future animal.”[272] Since, therefore, “No part engenders itself, but, after it is engendered, concurs in its own growth, it is indispensable that the part first arise which contains within itself the principle of increase; for whether it be a plant or an animal, still has it within itself the power of vegetation or nutrition;”[273] and at the same time distinguishes and fashions each particular part in its several order; and hence, in this same primogenate particle, there is a primary vital principle inherent, which is the author and original of sense and motion, and every manifestation of life.
That, therefore, is the principal particle whence vital spirit and native heat accrue to all other parts, in which the calidum innatum sive implantatum of physicians first shows itself, and the household deity or perennial fire is maintained; whence life proceeds to the body in general, and to each of its parts in particular; whence nourishment, growth, aid, and solace flow; lastly, where life first begins in the being that is born, and last fails in that which dies.
All this is certainly true as regards the first engendered part, and appears manifestly in the formation of the chick from the egg. I am therefore of opinion that we are to reject the views of certain physicians, indifferent philosophers, who will have it that three principal and primogenate parts arise together, viz.: the brain, the heart, and the liver; neither can I agree with Aristotle himself, who maintains that the heart is the first engendered and animated part; for I think that the privilege of priority belongs to the blood alone; the blood being that which is first seen of the newly engendered being, not only in the chick in ovo, but in the embryo of every animal whatsoever, as shall plainly be made to appear at a later stage of our inquiry.
There appears at first, I say, a red-coloured pulsating point or vesicle, with lines or canals extending from it, containing blood in their interior, and, in so far as we are enabled to perceive from the most careful examination, the blood is produced before the punctum saliens is formed, and is farther endowed with vital heat before it is put in motion by a pulse; so that as pulsation commences in it and from it, so, in the last struggle of mortal agony, does motion also end there. I have indeed ascertained by numerous experiments instituted upon the egg, as well as upon other subjects, that the blood is the element of the body in which, so long as the vital heat has not entirely departed, the power of returning to life is continued.
And since the pulsating vesicle and the sanguineous tubes extending thence are visible before anything else, I hold it as consonant with reason to believe that the blood is prior to its receptacles, the thing contained, to wit, to its container, inasmuch as this is made subservient to that. The vascular ramifications and the veins, therefore, after these the pulsating vesicle, and, finally, the heart, as being every one of them organs destined to receive and contain the blood, are, in all likelihood, constructed for the express purpose of impelling and distributing it, and the blood is, consequently, the principal portion of the body.
This conclusion is favoured by numerous observations; particularly by the fact that some animals, and these red-blooded, too, live for long periods without any pulse; some even lie concealed through the whole winter, and yet escape alive, though their heart had ceased from motion of every kind, and their lungs no longer played; they had lain in fact like those who lie half dead in a state of asphyxia from syncope, leipothymia, or the hysterical passion.
Emboldened by what I have observed both in studying the egg, and whilst engaged in the dissection of living animals, I maintain, against Aristotle, that the blood is the prime part that is engendered, and the heart the mere organ destined for its circulation. The function of the heart is the propulsion of the blood, as clearly appears in all animals furnished with red blood; and the office of the pulsating vesicle in the generation of the chick ab ovo, as well as in the embryos of mammiferous animals, is not different, a fact which I have repeatedly demonstrated to others, showing the vesicula pulsans as a feeble glancing spark, contracting in its action, now forcing out the blood which was contained in it, and again relaxing and receiving a fresh supply.
The supremacy of the blood farther appears from this, that the pulse is derived from it; for, as there are two parts in a pulsation, viz.: distension or relaxation, and contraction, or diastole and systole, and, as distension is the prior of these two motions, it is manifest that this motion proceeds from the blood; the contraction, again, from the vesicula pulsans of the embryo in ovo, from the heart in the pullet, in virtue of its own fibres, as an instrument destined for this particular end. Certain it is, that the vesicle in question, as also the auricle of the heart at a later period, whence the pulsation begins, is excited to the motion of contraction by the distending blood. The diastole, I say, takes place from the blood swelling, as it were, in consequence of containing an inherent spirit, so that the opinion of Aristotle in regard to the pulsation of the heart,—namely, that it takes place by a kind of ebullition,—is not without some mixture of truth; for what we witness every day in milk heated over the fire, and in beer that is brisk with fermentation, comes into play in the pulse of the heart; in which the blood, swelling with a sort of fermentation, is alternately distended and repressed; the same thing that takes place in the liquids mentioned through an external agent, namely adventitious heat, is effected in the blood by an intimate heat, or an innate spirit; and this, too, is regulated in conformity with nature by the vital principle (anima), and is continued to the benefit of animated beings.
The pulse, then, is produced by a double agent: first, the blood undergoes distension or dilatation, and secondly, the vesicular membrane of the embryo in the egg, the auricles and ventricles in the extruded chick, effect the constriction. By these alternating motions associated, is the blood impelled through the whole body, and the life of animals is thereby continued.
Nor is the blood to be styled the primigenial and principal portion of the body, because the pulse has its commencement in and through it; but also because animal heat originates in it, and the vital spirit is associated with it, and it constitutes the vital principle itself, (ipsa anima); for wheresoever the immediate and principal instrument of the vegetative faculty is first discovered, there also does it seem likely will the living principle be found to reside, and thence take its rise; seeing that the life is inseparable from spirit and innate heat.
For “however distinct are the artist and the instrument in things made by art,” as Fabricius[274] well reminds us, “in the works of nature they are still conjoined and one. Thus the stomach is the author and the organ of chylopoesis.” In like manner are the vital principle and its instrument immediately conjoined; and so, in whatever part of the body heat and motion have their origin, in this also must life take its rise, in this be last extinguished; and no one, I presume, will doubt that there are the lares and penates of life enshrined, that there the vital principle (anima) itself has its seat.
The life, therefore, resides in the blood, (as we are also informed in our sacred writings,)[275] because in it life and the soul first show themselves, and last become extinct. For I have frequently found, from the dissection of living animals, as I have said, that the heart of an animal that was dying, that was dead, and had ceased to breathe, still continued to pulsate for a time, and retained its vitality. The ventricles failing and coming to a stand, the motion still goes on in the auricles, and finally in the right auricle alone; and even when all motion has ceased, there the blood may still be seen affected with a kind of undulation and obscure palpitation or tremor, the last evidence of life. Every one, indeed, may perceive that the blood—this author of pulsation and life,—longest retains its heat; for when this is gone, and it is no longer blood, but gore, so is there, then, no hope of a return to life. But, truly, as has been stated, both in the chick in ovo and in the moribund animal, if you but apply some gentle stimulus either to the punctum saliens or to the right auricle of the heart after the failure of all pulsation, forthwith you will see motion, pulsation, and life restored to the blood—provided always, be it understood, that the innate heat and vital spirit have not been wholly lost.
From this it clearly appears that the blood is the generative part, the fountain of life, the first to live, the last to die, and the primary seat of the soul; the element in which, as in a fountain head, the heat first and most abounds and flourishes; from whose influxive heat all the other parts of the body are cherished, and obtain their life; for the heat, the companion of the blood, flows through and cherishes and preserves the whole body, as I formerly demonstrated in my work on the motion of the blood.
And since blood is found in every particle of the body, so that you can nowhere prick with a needle, nor make the slightest scratch, but blood will instantly appear, it seems as if, without this fluid, the parts could neither have heat nor life. So that the blood, being in ever so trifling a degree concentrated and fixed,—Hippocrates called the state ἀπύληψις τῶν φλεβῶν—stasis of the veins,—as in lipothymia, alarm, exposure to severe cold, and on the accession of a febrile paroxysm, the whole body is observed to become cold and torpid, and, overspread with pallor and livor, to languish. But the blood, recalled by stimulants, by exercise, by certain emotions of the mind, such as joy or anger, suddenly all is hot, and flushed, and vigorous, and beautiful again.
Therefore it is that the red and sanguine parts, such as the flesh, are alone spoken of as hot, and the white and bloodless parts, on the contrary, such as the tendons and ligaments, are designated as cold. And as red-blooded animals excel exsanguine creatures, so also, in our estimate of the parts, are those which are more liberally furnished with native heat and blood, held more excellent than all the others. The liver, spleen, kidneys, lungs, and heart itself,—parts which are especially entitled viscera,—if you will but squeeze out all the blood they contain, become pale and fall within the category of cold parts. The heart itself, I say, receives influxive heat and life along with the blood that reaches it, through the coronary arteries; and only so long as the blood has access to it. Neither can the liver perform its office without the influence of the blood and heat it receives through the cœliac artery; for there is no influx of heat without an afflux of blood by the arteries, and this is the reason wherefore, when parts are first produced, and before they have taken upon them the performance of their respective duties, they all look bloodless and pale, in consequence of which they were formerly regarded as spermatic by physicians and anatomists, and in generation it was usual to say that several days were passed in the milk. The liver, lungs, and substance of the heart itself, when they first appear, are extremely white; and, indeed, the cone of the heart and the walls of the ventricles are still seen to be white, when the auricles, replete with crimson blood, are red, and the coronary vein is purple with its stream. In like manner, the parenchyma of the liver is white, when its veins and their branches are red with blood; nor does it perform any duty until it is penetrated with blood.
The blood, in a word, so flows around and penetrates the whole body, and imparts heat and life conjoined to all its parts, that the vital principle, having its first and chief seat there, may truly be held as resident in the blood; in this way, in common parlance, it comes to be all in all, and all in each particular part.
But so little is it true, as Aristotle and the medical writers assert, that the liver and the heart are the authors and compounders of the blood, that the contrary even appears most obviously from the formation of the chick in ovo, viz.: that the blood is much rather the fashioner of the heart and liver; a fact, which physicians themselves appear unintentionally to confirm, when they speak of the parenchyma of the liver as a kind of effusion of blood, as if it were nothing more than so much blood coagulated there. But the blood must exist before it can either be shed or coagulated; and experience palpably demonstrates that the thing is so, seeing that the blood is already present before there is a vestige either of the body or of any viscus; and that in circumstances where none of the mother’s blood can by possibility reach the embryo, an event which is vulgarly held to occur among viviparous animals.
The liver of fishes is always perceived of a white colour, though their veins are of a deep purple or black; and our fowls, the fatter they become, the smaller and paler grows the liver. Cachectic maidens, and those who labour under chlorosis, are not only pale and blanched in their bodies generally, but in their livers as well, a manifest indication of a want of blood in their system. The liver, therefore, receives both its heat and colour from the blood; the blood is in no wise derived from the liver.
From what has now been said, then, it appears that the blood is the first engendered part, whence the living principle in the first instance gleams forth, and from which the first animated particle of the embryo is formed; that it is the source and origin of all other parts, both similar and dissimilar, which thence obtain their vital heat and become subservient to it in its duties. But the heart is contrived for the sole purpose of ministering between the veins and the arteries—of receiving blood from the veins, and, by its ceaseless contractions, of propelling it to all parts of the body through the arteries.
This fact is made particularly striking, when we find that neither is there a heart found in every animal, neither does it necessarily and in every instance pulsate at all times where it is encountered; the blood, however, or a fluid which stands in lieu of it, is never wanting.