William Harvey

“ It is in this interval that the transition is made in the egg from the life of the plant to the life of the animal. For now the margin of the diffluent fluid looks red, and is purpurescent with a sanguineous line, and nearly in its centre there appears a leaping point, of the colour of blood, so small that at one moment, when it contracts, it almost entirely escapes the eye, and again, when it dilates, it shows like the smallest spark of fire. Such at the outset is animal life, which the plastic force of nature puts in motion from the most insignificant beginnings! ”

“ Whence the stomach at length failing, and the excretions long retained, the work of concoction proceeding languidly, the liver getting loaded, the blood stagnating in the veins, the spirits frozen, the heart, the source of life, oppressed, the lungs infarcted, and made impervious to the ambient air, the general habit rendered more compact, so that it could no longer exhale or perspire—no wonder that the soul, little content with such a prison, took its flight. ”

“ It is as if the summer in England sufficed for the production of the fruit only, as the hen for the production of the egg, but like the female fowl was impotent as a pro-genetrix; whilst in other countries enjoying the sun’s light in larger proportion, the summer acquired the characters of the male, and perfected the work of generation. ”

“ 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. ”

“ 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. ”

“ 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.” ”

“ The egg is the terminus from which all fowls, male and female, have sprung, and to which all their lives tend,—it is the result which nature has proposed to herself in their being. And thus it comes that individuals in procreating their like for the sake of their species, endure for ever. The egg, I say, is a period or portion of this eternity; for it were hard to say whether an egg exists for the sake of the chick that it engenders, or the pullet exists for the sake of the egg which it is to engender. ”

“ This view of Fabricius is therefore both imperfect and incorrect; inasmuch as he does not think of what nature performs in fact in the work of generation, so much as of what in his opinion she ought to do, betrayed into this by his comparison with the edifice reared by art. As if nature had imitated art, and not rather art nature!—mindful of which he himself says afterwards: [288] “It were better to say that art learned of nature, and was an imitator of her doings; for, as Galen everywhere reminds us, nature is both older and displays greater wisdom in her works than art.” ”

“ But of this matter we shall speak more fully, when we come to treat of the soul or living principle of the embryo in general, and of the excellence and divine nature of the vegetative soul from a survey of its operations, all of which are carried on with such foresight, art, and divine intelligence; which, indeed, surpass our powers of understanding not less than Deity surpasses man, and are allowed, by common consent, to be so wonderful that their ineffable lustre is in no way to be penetrated by the dull edge of our apprehension. ”

“ The heart, consequently, is the beginning of life; the sun of the microcosm, even as the sun in his turn might well be designated the heart of the world; for it is the heart by whose virtue and pulse the blood is moved, perfected, made apt to nourish, and is preserved from corruption and coagulation; it is the household divinity which, discharging its function, nourishes, cherishes, quickens the whole body, and is indeed the foundation of life, the source of all action. ”

“ In such an egg, I ask, is it the vital principle of the father or that of the mother, which inheres? or is it a mixture of the two? But how can vital principles be mingled, if the vital principle (as form) be act and substance, which it is, according to Aristotle? For no one will deny, whatever it be ultimately which in the fruitful egg is the beginning and cause of the effects we witness, that it is a substance susceptible of divers powers, forces, or faculties, and even conditions,—virtues, vices, health and sickness. For some eggs are esteemed to be longer, others shorter lived ”

“ In so far as it is spirit, it is the hearth, the Vesta, the household divinity, the innate heat, the sun of the microcosm, the fire of Plato; not because like common fire it lightens, burns, and destroys, but because by a vague and incessant motion it preserves, nourishes, and aggrandizes itself. It farther deserves the name of spirit, inasmuch as it is radical moisture, at once the ultimate and the proximate and the primary aliment, more abundant than all the other parts ”

“ 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 indeed men were first led to cultivate philosophy from wondering at what they saw. For my own part, then, when I see nothing left in the uterus after intercourse to which I can ascribe the principle of generation, any more than there is in the brain anything discoverable after sensation and experience, which are the prime sources of art, and when I find the structure of both alike, I have devised this fable. ”

“ 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. ”

“ Which and what principle is it whence motion and generation proceed? By what virtue does the semen act, according to Aristotle? What is it that renders the semen itself fruitful? (for the philosopher will have it that nature in all natural bodies is the innate principle of motion and of rest, and not any second accident.) Whether is that which in the egg is cause, artificer, and principle of generation and of all the vital and vegetative operations—conservation, nutrition, growth—innate or superadded? ”

“ We are, I say, to strive after personal experience, not to rely on the experience of others; without which, indeed, no one can properly become a student of any branch of natural science, nor show himself a competent judge of what I am about to say on the subject of generation; for without experience and skill in anatomy, he would not better understand me than could one born blind appreciate the nature and difference of colours, or one deaf from birth judge of sounds. I would, therefore, have you, gentle reader, to take nothing on trust from me concerning the generation of animals ”

“ 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 ”

“ Nor do they err less who, with Democritus, compose all things of atoms; or with Empedocles, of elements. As if generation were nothing more than a separation, or aggregation, or disposition of things. It is not indeed to be denied, that when one thing is to be produced from another, all these are necessary, but generation itself is different from them all. I find Aristotle to be of this opinion; and it is my intention, by-and-by, to teach that out of the same albumen (which all allow to be uniform, not composed of diverse parts,) all the parts of the chick, bones, nails, feathers, flesh, &c. ”

“ Thus, our learned anatomist, blinded by a popular error, seeking in the egg for some particular matter fitted to engender the chick distinct from the rest of the contents of the egg, has gone astray. And so it happens to all, who forsaking the light, which the frequent dissection of bodies, and familiar converse with nature supplies, expect that they are to understand from conjecture, and arguments founded on probabilities, or the authority of writers, the things or the facts which they ought themselves to behold with their own eyes, to perceive with their proper senses. ”

“ Nor in truth is it a much less arduous business to investigate the intimate mysteries and obscure beginnings of generation than to seek to discover the frame of the world at large, and the manner of its creation. The eternity of things is connected{226} with the reciprocal interchange of generation and decay; and as the sun, now in the east and then in the west, completes the measure of time by his ceaseless revolutions, so are the fleeting things of mortal existence made eternal through incessant change, and kinds and species are perpetuated though individuals die. ”

“ The heart, ready furnished with its proper organs of motion, like a kind of internal creature, is of a date anterior to the body: first formed, nature willed that it should afterwards fashion, nourish, preserve, complete the entire animal, as its work and dwelling place: the heart, like the prince in a kingdom, in whose hands lie the chief and highest authority, rules over all; it is the original and foundation from which all power is derived, on which all power depends in the animal body. ”

“ They, consequently, who refuse such remarkable faculties to the blood, and go to heaven to fetch down I know not what spirits, to which they ascribe these divine virtues, cannot know, or at all events, cannot consider that the process of generation, and even of nutrition, which indeed is a kind of generation, for the sake of which they are so lavish of admirable properties, surpasses the powers of those very spirits themselves, nor of the spirits only, but of the vegetative, aye, even the sensitive, and I will venture to add, the rational soul. ”

“ Hence are we farther made more certain as to the commencement of animal generation and the prime inherent principle of the egg. For it is assuredly known that the cicatricula or spot on the yelk is the chief point in the egg, that to which all the rest are subordinate, and to which, if to any one thing more than another, is to be referred the cause, whatever it be, of fecundity in the egg:—certain it is that the generation of the embryo is begun within its precincts. ”

“ He is also mistaken when he would have the vegetative portion of the vital principle prior in nature and time to the sensitive and motive element. For that which is prior in nature is mostly posterior in the order of generation. In point of time, indeed, the vegetative principle is prior; because without it the sensitive principle cannot exist: an act—if the act of an organic body—cannot take place without organs; and the sensitive and motive organs are the work of the vegetative principle; the sensitive soul before the existence of action, is like a triangle within a quadrangle. ”

“ More than this, Fabricius has slipped the greatest difficulty of all, the source of not a little doubt and debate to the medical mind, viz. how the liver should be the source and artificer of the blood, seeing that this fluid not only exists in the egg before any viscus is formed, but that all medical writers teach that the parenchymata of the viscera are but effusions of blood? Is the work the author of its workman? If the parenchyma of the liver come from the blood, how can it be the cause of the blood? ”

“ By what reasoning should we give the blind from birth to know that the sun was luminous, and far surpassed the stars in brightness? And so it is with the circulation of the blood, which the world has now had before it for so many years, illustrated by proofs cognizable by the senses, and confirmed by various experiments. No one has yet been found to dispute the sensible facts, the motion, efflux and afflux of the blood, by like observations based on the evidence of sense, or to oppose the experiments adduced, by other experiments of the same character ”

“ There is, in fact, no occasion for searching after spirits foreign to, or distinct from, the blood; to evoke heat from another source; to bring gods upon the scene, and to encumber philosophy with any fanciful conceits; what we are wont to derive from the stars is in truth produced at home: the blood is the only calidum innatum, or first engendered animal heat; a fact which so clearly appears from our observations on animal reproduction, particularly of the chick from the egg, that it seems superfluous to multiply illustrations. ”

“ Let us conclude, therefore, that the male, although a prior and more excellent efficient than the female, is still no more than an instrumental efficient, and that he, not less than the female, must refer his fecundity or faculty of engendering as received from the approaching sun; and, consequently, that the skill and foresight, which are apparent in his work, are not to be held as proceeding from him but from God; inasmuch as the male in the act of kind neither uses counsel nor understanding; neither does man engender the rational part of his soul, but only the vegetative faculty ”

“ But how can parts attract in which the heat and life are almost extinct? Or how should they whose passages are filled with condensed and frigid blood, admit fresh aliment—renovated blood—unless they had first got rid of their old contents? Unless the heart were truly that fountain where life and heat are restored to the refrigerated fluid, and whence new blood, warm, imbued with spirits, being sent out by the arteries, that which has become cooled and effete is forced on, and all the particles recover their heat which was failing, and their vital stimulus well-nigh exhausted. ”