How difficult is it to teach those who have no experience, the things of

which they have not any knowledge by their senses! And how useless and

intractable, and unimpregnable to true science are such auditors! They

show the judgment of the blind in regard to colours, of the deaf in

reference to concords. Who ever pretended to teach the ebb and flow of

the tide, or from a diagram to demonstrate the measurements of the

angles and the proportions of the sides of a triangle to a blind man, or

to one who had never seen the sea nor a diagram? He who is not

conversant with anatomy, inasmuch as he forms no conception of the

subject from the evidence of his own eyes, is virtually blind to all

that concerns anatomy, and unfit to appreciate what is founded thereon;

he knows nothing of that which occupies the attention of the anatomist,

nor of the principles inherent in the nature of the things which guide

him in his reasonings; facts and inferences as well as their sources are

alike unknown to such a one. But no kind of science can possibly flow,

save from some pre-existing knowledge of more obvious things; and this

is one main reason why our science in regard to the nature of celestial

bodies, is so uncertain and conjectural. I would ask of those who

profess a knowledge of the causes of all things, why the two eyes keep

constantly moving together, up or down, to this side or to that, and not

independently, one looking this way another that; why the two auricles

of the heart contract simultaneously, and the like? Are fevers,

pestilence, and the wonderful properties of various medicines to be

denied because their causes are unknown? Who can tell us why the fœtus

in utero, breathing no air up to the tenth month of its existence, is

yet not suffocated? born in the course of the seventh or eighth month,

and having once breathed, it is nevertheless speedily suffocated if its

respiration be interrupted. Why can the fœtus still contained within the

uterus, or enveloped in the membranes, live without respiration; whilst

once exposed to the air, unless it breathes it inevitably dies?[116]

Observing that many hesitate to acknowledge the circulation, and others

oppose it, because, as I conceive, they have not rightly understood me,

I shall here recapitulate briefly what I have said in my work on the

Motion of the Heart and Blood. The blood contained in the veins, in its

magazine, and where it is collected in largest quantity, viz., in the

vena cava, close to the base of the heart and right auricle, gradually

increasing in temperature by its internal heat, and becoming attenuated,

swells and rises like bodies in a state of fermentation, whereby the

auricle being dilated, and then contracting, in virtue of its pulsative

power, forthwith delivers its charge into the right ventricle; which

being filled, and the systole ensuing, the charge, hindered from

returning into the auricle by the tricuspid valves, is forced into the

pulmonary artery, which stands open to receive it, and is immediately

distended with it. Once in the pulmonary artery, the blood cannot

return, by reason of the sigmoid valves; and then the lungs, alternately

expanded and contracted during inspiration and expiration, afford it

passage by the proper vessels into the pulmonary veins; from the

pulmonary veins, the left auricle, acting equally and synchronously with

the right auricle, delivers the blood into the left ventricle; which

acting harmoniously with the right ventricle, and all regress being

prevented by the mitral valves, the blood is projected into the aorta,

and consequently impelled into all the arteries of the body. The

arteries, filled by this sudden push, as they cannot discharge

themselves so speedily, are distended; they receive a shock, or undergo

their diastole. But as this process goes on incessantly, I infer that

the arteries both of the lungs and of the body at large, under the

influence of such a multitude of strokes of the heart and injections of

blood, would finally become so over-gorged and distended, that either

any further injection must cease, or the vessels would burst, or the

whole blood in the body would accumulate within them, were there not an

exit provided for it.

The same reasoning is applicable to the ventricles of the heart:

distended by the ceaseless action of the auricles, did they not

disburthen themselves by the channels of the arteries, they would by and

by become over-gorged, and be fixed and made incapable of all motion.

Now this, my conclusion, is true and necessary, if my premises be true;

but that these are either true or false, our senses must inform us, not

our reason--ocular inspection, not any process of the mind.

I maintain further, that the blood in the veins always and everywhere

flows from less to greater branches, and from every part towards the

heart; whence I gather that the whole charge which the arteries receive,

and which is incessantly thrown into them, is delivered to the veins,

and flows back by them to the source whence it came. In this way,

indeed, is the circulation of the blood established: by an efflux and

reflux from and to the heart; the fluid being forcibly projected into

the arterial system, and then absorbed and imbibed from every part by

the veins, it returns through these in a continuous stream. That all

this is so, sense assures us; and necessary inference from the

perceptions of sense takes away all occasion for doubt. Lastly, this is

what I have striven, by my observations and experiments, to illustrate

and make known; I have not endeavoured from causes and probable

principles to demonstrate my propositions, but, as of higher authority,

to establish them by appeals to sense and experiment, after the manner

of anatomists.

And here I would refer to the amount of force, even of violence, which

sight and touch make us aware of in the heart and greater arteries; and

to the systole and diastole constituting the pulse in the large

warm-blooded animals, which I do not say is equal in all the vessels

containing blood, nor in all animals that have blood; but which is of

such a nature and amount in all, that a flow and rapid passage of the

blood through the smaller arteries, the interstices of the tissues, and

the branches of the veins, must of necessity take place; and therefore

there is a circulation.

For neither do the most minute arteries, nor the veins, pulsate; but the

larger arteries and those near the heart pulsate, because they do not

transmit the blood so quickly as they receive it.[117] Having exposed an

artery, and divided it so that the blood shall flow out as fast and

freely as it is received, you will scarcely perceive any pulse in that

vessel; and for the simple reason, that an open passage being afforded,

the blood escapes, merely passing through the vessel, not distending it.

In fishes, serpents, and the colder animals, the heart beats so slowly

and feebly, that a pulse can scarcely be perceived in the arteries; the

blood in them is transmitted gradually. Whence in them, as also in the

smaller branches of the arteries in man, there is no distinction between

the coats of the arteries and veins, because the arteries have to

sustain no shock from the impulse of the blood.

An artery denuded and divided in the way I have indicated, sustains no

shock, and therefore does not pulsate; whence it clearly appears that

the arteries have no inherent pulsative power, and that neither do they

derive any from the heart; but that they undergo their diastole solely

from the impulse of the blood; for in the full stream, flowing to a

distance, you may see the systole and diastole, all the motions of the

heart--their order, force, rhythm, &c.,[118] as it were in a mirror,

and even perceive them by the touch. Precisely as in the water that is

forced aloft, through a leaden pipe, by working the piston of a

forcing-pump, each stroke of which, though the jet be many feet distant,

is nevertheless distinctly perceptible,--the beginning, increasing

strength, and end of the impulse, as well as its amount, and the

regularity or irregularity with which it is given, being indicated, the

same precisely is the case from the orifice of a divided artery; whence,

as in the instance of the forcing engine quoted, you will perceive that

the efflux is uninterrupted, although the jet is alternately greater and

less. In the arteries, therefore, besides the concussion or impulse of

the blood, the pulse or beat of the artery, which is not equally

exhibited in all, there is a perpetual flow and motion of the blood,

which returns in an unbroken stream to the point from whence it

commenced--the right auricle of the heart.

All these points you may satisfy yourself upon, by exposing one of the

longer arteries, and having taken it between your finger and thumb,

dividing it on the side remote from the heart. By the greater or less

pressure of your fingers, you can have the vessel pulsating less or

more, or losing the pulse entirely, and recovering it at will. And as

these things proceed thus when the chest is uninjured, so also do they

go on for a short time when the thorax is laid open, and the lungs

having collapsed, all the respiratory motions have ceased; here,

nevertheless, for a little while you may perceive the left auricle

contracting and emptying itself, and becoming whiter; but by and by

growing weaker and weaker, it begins to intermit, as does the left

ventricle also, and then it ceases to beat altogether, and becomes

quiescent. Along with this, and in the same measure, does the stream of

blood from the divided artery grow less and less, the pulse of the

vessel weaker and weaker, until at last, the supply of blood and the

impulse of the left ventricle failing, nothing escapes from it. You may

perform the same experiment, tying the pulmonary veins, and so taking

away the pulse of the left auricle, or relaxing the ligature, and

restoring it at pleasure. In this experiment, too, you will observe what

happens in moribund animals, viz., that the left ventricle first ceases

from pulsation and motion, then the left auricle, next the right

ventricle, finally the right auricle; so that where the vital force and

pulse first begin, there do they also last fail.

All of these particulars having been recognized by the senses, it is

manifest that the blood passes through the lungs, not through the septum

[in its course from the right to the left side of the heart], and only

through them when they are moved in the act of respiration, not when

they are collapsed and quiescent; whence we see the probable reason

wherefore nature has instituted the foramen ovale in the fœtus, instead

of sending the blood by the way of the pulmonary artery into the left

auricle and ventricle, which foramen she closes when the new-born

creature begins to breathe freely. We can also now understand why, when

the vessels of the lungs become congested and oppressed, and in those

who are affected with serious diseases, it should be so dangerous and

fatal a symptom when the respiratory organs become implicated.

We perceive further, why the blood is so florid in the lungs, which is,

because it is thinner, as having there to undergo filtration.

Still further; from the summary which precedes, and by way of satisfying

those who are importunate in regard to the causes of the circulation,

and incline to regard the power of the heart as competent to

everything--as that it is not only the seat and source of the pulse

which propels the blood, but also, as Aristotle thinks, of the power

which attracts and produces it; moreover, that the spirits are

engendered by the heart, and the influxive vital heat, in virtue of the

innate heat of the heart, as the immediate instrument of the soul, or

common bond and prime organ in the performance of every act of vitality;

in a word, that the motion, perfection, heat, and every property besides

of the blood and spirits are derived from the heart, as their fountain

or original, (a doctrine as old as Aristotle, who maintained all these

qualities to inhere in the blood, as heat inheres in boiling water or

pottage,) and that the heart is the primary cause of pulsation and life;

to those persons, did I speak openly, I should say that I do not agree

with the common opinion; there are numerous particulars to be noted in

the production of the parts of the body which incline me this way, but

which it does not seem expedient to enter upon here. Before long,

perhaps, I shall have occasion to lay before the world things that are

more wonderful than these, and that are calculated to throw still

greater light upon natural philosophy.

Meantime I shall only say, and, without pretending to demonstrate it,

propound--with the good leave of our learned men, and with all respect

for antiquity--that the heart, with the veins and arteries and the blood

they contain, is to be regarded as the beginning and author, the

fountain and original of all things in the body, the primary cause of

life; and this in the same acceptation as the brain with its nerves,

organs of sense and spinal marrow inclusive, is spoken of as the one and

general organ of sensation. But if by the word heart the mere body of

the heart, made up of its auricles and ventricles, be understood, then I

do not believe that the heart is the fashioner of the blood; neither do

I imagine that the blood has powers, properties, motion, or heat, as the

gift of the heart; lastly, neither do I admit that the cause of the

systole and contraction is the same as that of the diastole or

dilatation, whether in the arteries, auricles, or ventricles; for I hold

that that part of the pulse which is designated the diastole depends on

another cause different from the systole, and that it must always and

everywhere precede any systole; I hold that the innate heat is the first

cause of dilatation, and that the primary dilatation is in the blood

itself, after the manner of bodies in a state of fermentation, gradually

attenuated and swelling, and that in the blood is this finally

extinguished; I assent to Aristotle’s example of gruel or milk upon the

fire, to this extent, that the rising and falling of the blood does not

depend upon vapours or exhalations, or spirits, or anything rising in a

vaporous or aëreal shape, nor upon any external agency, but upon an

internal principle under the control of nature.

Nor is the heart, as some imagine, anything like a chauffer or fire, or

heated kettle, and so the source of the heat of the blood; the blood,

instead of receiving, rather gives heat to the heart, as it does to all

the other parts of the body; for the blood is the hottest element in the

body; and it is on this account that the heart is furnished with

coronary arteries and veins; it is for the same reason that other parts

have vessels, viz., to secure the access of warmth for their due

conservation and stimulation; so that the warmer any part is, the

greater is its supply of blood, or otherwise; where the blood is in

largest quantity, there also is the heat highest. For this reason is the

heart, remarkable through its cavities, to be viewed as the elaboratory,

fountain, and perennial focus of heat, and as comparable to a hot

kettle, not because of its proper substance, but because of its

contained blood; for the same reason, because they have numerous veins

or vessels containing blood, are the liver, spleen, lungs, &c., reputed

hot parts. And in this way do I view the native or innate heat as the

common instrument of every function, the prime cause of the pulse among

the rest. This, however, I do not mean to state absolutely, but only

propose it by way of thesis. Whatever may be objected to it by good and

learned men, without abusive or contemptuous language, I shall be ready

to listen to--I shall even be most grateful to any one who will take up

and discuss the subject.

These then, are, as it were, the very elements and indications of the

passage and circulation of the blood, viz., from the right auricle into

the right ventricle; from the right ventricle by the way of the lungs

into the left auricle; thence into the left ventricle and aorta; whence

by the arteries at large through the pores or interstices of the tissues

into the veins, and by the veins back again with great rapidity to the

base of the heart.

There is an experiment on the veins by which any one that chooses may

convince himself of this truth: Let the arm be bound with a moderately

tight bandage, and then, by opening and shutting the hand, make all the

veins to swell as much as possible, and the integuments below the fillet

to become red; and now let the arm and hand be plunged into very cold

water, or snow, until the blood pent up in the veins shall have become

cooled down; then let the fillet be undone suddenly, and you will

perceive, by the cold blood returning to the heart, with what celerity

the current flows, and what an effect it produces when it has reached

the heart; so that you will no longer be surprised that some should

faint when the fillet is undone after venesection.[119] This experiment

shows that the veins swell below the ligature not with attenuated blood,

or with blood raised by spirits or vapours, for the immersion in the

cold water would repress their ebullition, but with blood only, and such

as could never make its way back into the arteries, either by

open-mouthed communications or by devious passages; it shows, moreover,

how and in what way those who are travelling over snowy mountains are

sometimes stricken suddenly with death, and other things of the same

kind.

Lest it should seem difficult for the blood to make its way through the

pores of the various structures of the body, I shall add one

illustration: The same thing happens in the bodies of those that are

hanged or strangled, as in the arm that is bound with a fillet: all the

parts beyond the noose,--the face, lips, tongue, eyes, and every part of

the head appear gorged with blood, swollen and of a deep red or livid

colour; but if the noose be relaxed, in whatever position you have the

body, before many hours have passed you will perceive the whole of the

blood to have quitted the head and face, and gravitated through the

pores of the skin, flesh, and other structures, from the superior parts

towards those that are inferior and dependent, until they become tumid

and of a dark colour. But if this happens in the dead body, with the

blood dead and coagulated, the frame stiffened with the chill of death,

the passages all compressed or blocked up, it is easy to perceive how

much more apt it will be to occur in the living subject, when the blood

is alive and replete with spirits, when the pores are all open, the

fluid ready to penetrate, and the passage in every way made easy.

When the ingenious and acute Descartes, (whose honourable mention of my

name demands my acknowledgments,) and others, having taken out the heart

of a fish, and put it on a plate before them, see it continuing to

pulsate (in contracting), and when it raises or erects itself and

becomes firm to the touch, they think it enlarges, expands, and that its

ventricles thence become more capacious. But, in my opinion, they do not

observe correctly; for, at the time the heart gathers itself up, and

becomes erect, it is certain that it is rather lessened in every one of

its dimensions; that it is in its systole, in short, not in its

diastole. Neither, on the contrary, when it collapses and sinks down, is

it then properly in its state of diastole and distension, by which the

ventricles become more capacious. But as we do not say that the heart is

in the state of diastole in the dead body, as having sunk relaxed after

the systole, but is then collapsed, and without all motion--in short is

in a state of rest, and not distended. It is only truly distended, and

in the proper state of diastole, when it is filled by the charge of

blood projected into it by the contraction of the auricles; a fact which

sufficiently appears in the course of vivisections. Descartes therefore

does not perceive how much the relaxation and subsidence of the heart

and arteries differ from their distension or diastole; and that the

cause of the distension, relaxation, and constriction, is not one and

the same; as contrary effects so must they rather acknowledge contrary

causes; as different movements they must have different motors; just as

all anatomists know that the flexion and extension of an extremity are

accomplished by opposite antagonist muscles, and contrary or diverse

motions are necessarily performed by contrary and diverse organs

instituted by nature for the purpose. Neither do I find the efficient

cause of the pulse aptly explained by this philosopher, when with

Aristotle he assumes the cause of the systole to be the same as that of

the diastole, viz., an effervescence of the blood due to a kind of

ebullition. For the pulse is a succession of sudden strokes and quick

percussions; but we know of no kind of fermentation or ebullition in

which the matter rises and falls in the twinkling of an eye; the heaving

is always gradual where the subsidence is notable. Besides, in the body

of a living animal laid open, we can with our eyes perceive the

ventricles of the heart both charged and distended by the contraction of

the auricles, and more or less increased in size according to the

charge; and farther, we can see that the distension of the heart is

rather a violent motion, the effect of an impulsion, and not performed

by any kind of attraction.

Some are of opinion that, as no kind of impulse of the nutritive juices

is required in vegetables, but that these are attracted by the parts

which require them, and flow in to take the place of what has been lost;

so neither is there any necessity for an impulse in animals, the

vegetative faculty in both working alike. But there is a difference

between plants and animals. In animals, a constant supply of warmth is

required to cherish the members, to maintain them in life by the

vivifying heat, and to restore parts injured from without. It is not

merely nutrition that has to be provided for.

So much for the circulation; any impediment, or perversion, or excessive

excitement of which, is followed by a host of dangerous diseases and

remarkable symptoms: in connexion with the veins--varices,

abscesses, pains, hemorrhoids, hemorrhages; in connexion with the

arteries--enlargements, phlegmons, severe and lancinating pains,

aneurisms, sarcoses, fluxions, sudden attacks of suffocation, asthmas,

stupors, apoplexies, and innumerable other affections. But this is not

the place to enter on the consideration of these; neither may I say

under what circumstances and how speedily some of these diseases, that

are even reputed incurable, are remedied and dispelled, as if by

enchantment. I shall have much to put forth in my Medical Observations

and Pathology, which, so far as I know, has as yet been observed by no

one.

That I may afford you still more ample satisfaction, most learned

Riolanus, as you do not think there is a circulation in the vessels of

the mesentery, I shall conclude by proposing the following experiment:

throw a ligature around the porta close to the liver, in a living

animal, which is easily done. You will forthwith perceive the veins

below the ligature swelling in the same way as those of the arm when the

bleeding fillet is bound above the elbow; a circumstance which will

proclaim the course of the blood there. And as you still seem to think

that the blood can regurgitate from the veins into the arteries by open

anastomoses, let the vena cava be tied in a living animal near the

divarication of the crural veins, and immediately afterwards let an

artery be opened to give issue to the blood: you will soon observe the

whole of the blood discharged from all the veins, that of the ascending

cava among the number, with the single exception of the crural veins,

which will continue full; and this certainly could not happen were there

any retrograde passage for the blood from the veins to the arteries by

open anastomoses.

ANATOMICAL EXERCISES

ON

THE GENERATION OF ANIMALS;

TO WHICH ARE ADDED

ESSAYS ON PARTURITION; ON THE MEMBRANES, AND FLUIDS OF

THE UTERUS; AND ON CONCEPTION.

BY WILLIAM HARVEY,

DOCTOR OF PHYSIC, AND PROFESSOR OF ANATOMY AND SURGERY

IN THE COLLEGE OF PHYSICIANS OF LONDON.

LONDON, 1651.

To the learned and illustrious the President and Fellows of the

College of Physicians of London.

Harassed with anxious, and in the end not much availing cares, about

Christmas last,[120] I sought to rid my spirit of the cloud that

oppressed it, by a visit to that great man, the chief honour and

ornament of our College, Dr. WILLIAM HARVEY, then dwelling not far from

the city. I found him, Democritus like, busy with the study of natural

things, his countenance cheerful, his mind serene, embracing all within

its sphere. I forthwith saluted him, and asked if all were well with

him? “How can it,” said he, “whilst the Commonwealth is full of

distractions, and I myself am still in the open sea? And truly,” he

continued, “did I not find solace in my studies, and a balm for my

spirit in the memory of my observations of former years, I should feel

little desire for longer life. But so it has been, that this life of

obscurity, this vacation from public business, which causes tedium and

disgust to so many, has proved a sovereign remedy to me.”

I answering said, “I can readily account for this: whilst most men are

learned through others’ wits, and under cover of a different diction and

a new arrangement, vaunt themselves on things that belong to the

ancients, thou ever interrogatest Nature herself concerning her

mysteries. And this line of study as it is less likely to lead into

error, so is it also more fertile in enjoyment, inasmuch as each

particular point examined often leads to others which had not before

been surmised. You yourself, I well remember, informed me once that you

had never dissected any animal--and many and many a one have you

examined,--but that you discovered something unexpected, something of

which you were formerly uninformed.”

“It is true,” said he: “the examination of the bodies of animals has

always been my delight; and I have thought that we might thence not only

obtain an insight into the lighter mysteries of nature, but there

perceive a kind of image or reflex of the omnipotent Creator himself.

And though much has already been made out by the learned men of former

times, I have still thought that much more remained behind, hidden by

the dusky night of nature, uninterrogated; so that I have oftentimes

wondered and even laughed at those who have fancied that everything had

been so consummately and absolutely investigated by an Aristotle or a

Galen, or some other mighty name, that nothing could by possibility be

added to their knowledge. Nature, however, is the best and most faithful

interpreter of her own secrets; and what she presents either more

briefly or obscurely in one department, that she explains more fully and

clearly in another. No one indeed has ever rightly ascertained the use

or function of a part who has not examined its structure, situation,

connexions by means of vessels, and other accidents, in various animals,

and carefully weighed and considered all he has seen. The ancients, our

authorities in science, even as their knowledge of geography was limited

by the boundaries of Greece, so neither did their knowledge of animals,

vegetables, and other natural objects extend beyond the confines of

their country. But to us the whole earth lies open, and the zeal of our

travellers has made us familiar not only with other countries and the

manners and customs of their inhabitants, but also with the animals,

vegetables, and minerals that are met with in each. And truly there is

no nation so barbarous which has not discovered something for the

general good, whether led to it by accident or compelled by necessity,

which had been overlooked by more civilized communities. But shall we

imagine that nothing can accrue to the wide domains of science from such

advantages, or that all knowledge was exhausted by the first ages of the

world? If we do, the blame very certainly attaches to our indolence,

nowise to nature.

“To this there is another evil added: many persons, wholly without

experience, from the presumed verisimilitude of a previous opinion, are

often led by and by to speak of it boldly, as a matter that is certainly

known; whence it comes, that not only are they themselves deceived, but

that they likewise lead other incautious persons into error.”

Discoursing in this manner, and touching upon many topics besides with

wonderful fluency and facility, as is his custom, I interposed by

observing, “How free you yourself are from the fault you indicate all

know who are acquainted with you; and this is the reason wherefore the

learned world, who are aware of your unwearied industry in the study of

philosophy, are eagerly looking for your farther experiments.”

“And would you be the man,” said Harvey, smiling, “who should recommend

me to quit the peaceful haven, where I now pass my life, and launch

again upon the faithless sea? You know full well what a storm my former

lucubrations raised. Much better is it oftentimes to grow wise at home

and in private, than by publishing what you have amassed with infinite

labour, to stir up tempests that may rob you of peace and quiet for the

rest of your days.”

“True,” said I; “it is the usual reward of virtue to have received ill

for having merited well. But the winds which raised those storms, like

the north-western blast, which drowns itself in its own rain, have only

drawn mischief on themselves.”

Upon this he showed me his ‘Exercises on the Generation of Animals,’ a

work composed with vast labour and singular care; and having it in my

hands, I exclaimed, “Now have I what I so much desired! and unless you

consent to make this work public, I must say that you will be wanting

both to your own fame and to the public usefulness. Nor let any fear of

farther trouble in the matter induce you to withhold it longer: I gladly

charge myself with the whole business of correcting the press.”

Making many difficulties at first, urging, among other things, that his

work must be held imperfect, as not containing his investigations on the

generation of insects, I nevertheless prevailed at length, and he said

to me, “I intrust these papers to your care with full authority either

speedily to commit them to the press, or to suppress them till some

future time.” Having returned him many thanks, I bade him adieu, and

took my leave, feeling like another Jason laden with the golden fleece.

On returning home I forthwith proceeded to examine my prize in all its

parts, and could not but wonder with myself that such a treasure should

have lain so long concealed; and that whilst others produce their

trifles and emptinesses with much ado, their messes twice, aye, an

hundred times, heated up, our Harvey should set so little store by his

admirable observations. And indeed, so often as he has sent forth any of

his discoveries to the world, he has not comported himself like those

who, when they publish, would have us believe that an oak had spoken,

and that they had merited the rarest honours,--a draught of hen’s milk

at the least. Our Harvey rather seems as though discovery were natural

to him, a thing of ease and of course, a matter of ordinary business;

though he may nevertheless have expended infinite labour and study on

his works. And we have evidence of his singular candour in this, that he

never hostilely attacks any previous writer, but ever courteously sets

down and comments upon the opinions of each; and indeed he is wont to

say, that it is argument of an indifferent cause when it is contended

for with violence and distemper; and that truth scarce wants an

advocate.

It would have been easy for our illustrious colleague to have woven the

whole of this web from materials of his own; but to escape the charge of

envy, he has rather chosen to take Aristotle and Fabricius of

Aquapendente as his guides, and to appear as contributing but his

portion to the general fabric. Of him, whose virtue, candour, and genius

are so well known to you all, I shall say no more, lest I should seem to

praise to his face one whose singular worth has exalted him beyond the

reach of all praise. Of myself I shall only say, that I have done no

more than perform the midwife’s office in this business, ushering into

the light this product of our colleague’s genius as you see it,

consummate and complete, but long delayed, and fearing perchance some

envious blast: in other words, I have overlooked the press; and as our

author writes a hand which no one without practice can easily read (a

thing that is common among our men of letters), I have taken some pains

to prevent the printer committing any very grave blunders through

this--a point which I observe not to have been sufficiently attended to

in the small work of his which lately appeared.[121]

Here then, my learned friends, you have the cause of my addressing you

at this time, viz. that you may know that our Harvey presents an

offering to the benefit of the republic of letters, to your honour, to

his own eternal fame.

Farewell, and prosper.

GEORGE ENT.

INTRODUCTION.

It will not, I trust, be unwelcome to you, candid reader, if I yield to

the wishes, I might even say the entreaties, of many, and in these

Exercises on Animal Generation, lay before the student and lover of

truth what I have observed on this subject from anatomical dissections,

which turns out to be very different from anything that is delivered by

authors, whether philosophers or physicians.

Physicians, following Galen, teach that from the semen of the male and

female mingled in coition the offspring is produced, and resembles one

or other, according to the _predominance_ of this one or of that; and

farther, that in virtue of the same predominance, it is either male or

female. Sometimes they declare the semen masculinum as the _efficient

cause_, and the semen femininum as supplying the _matter_; and

sometimes, again, they advocate precisely the opposite doctrine.

Aristotle, one of Nature’s most diligent inquirers, however affirms the

_principles_ of generation to be the male and the female, she

contributing the matter, he the form; and that immediately after the

sexual act the vital principle and the first particle of the future

fœtus, viz. the heart, in animals that have red blood, are formed from

the menstrual blood in the uterus.

But that these are erroneous and hasty conclusions is easily made to

appear: like phantoms of darkness they suddenly vanish before the light

of anatomical inquiry. Nor is any long refutation necessary where the

truth can be seen with one’s proper eyes; where the inquirer by simple

inspection finds everything in conformity with reason; and where at the

same time he is made to understand how unsafe, how base a thing it is to

receive instruction from others’ comments without examination of the

objects themselves, the rather as the book of Nature lies so open and is

so easy of consultation.

What I shall deliver in these my Exercises on Animal Generation I am

anxious to make publicly known, not merely that posterity may there

perceive the sure and obvious truth, but farther, and especially, that

by exhibiting the method of investigation which I have followed, I may

propose to the studious a new and, unless I mistake, a safer way to the

attainment of knowledge.

For although it is a new and difficult road in studying nature, rather

to question things themselves than, by turning over books, to discover

the opinions of philosophers regarding them, still it must be

acknowledged that it is the more open path to the secrets of natural

philosophy, and that which is less likely to lead into error.

Nor is there any just cause wherefore the labour should deter any one,

if he will but think that he himself only lives through the ceaseless

working of his heart. Neither, indeed, would the way I propose be felt

as so barren and lonely, but for the custom, or vice rather, of the age

we live in, when men, inclined to idleness, prefer going wrong with the

many, to becoming wise with the few through dint of toil and outlay of

money. The ancient philosophers, whose industry even we admire, went a

different way to work, and by their unwearied labour and variety of

experiments, searching into the nature of things, have left us no

doubtful light to guide us in our studies. In this way it is that almost

everything we yet possess of note or credit in philosophy, has been

transmitted to us through the industry of ancient Greece. But when we

acquiesce in the discoveries of the ancients, and believe (which we are

apt to do through indolence) that nothing farther remains to be known,

we suffer the edge of our ingenuity to be taken off, and the lamp which

they delivered to us to be extinguished. No one of a surety will allow

that all truth was engrossed by the ancients, unless he be utterly

ignorant (to pass by other arts for the present) of the many remarkable

discoveries that have lately been made in anatomy, these having been

principally achieved by individuals who, either intent upon some

particular matter, fell upon the novelty by accident, or (and this is

the more excellent way) who following the traces of nature with their

own eyes, pursued her through devious but most assured ways till they

reached her in the citadel of truth. And truly in such pursuits it is

sweet not merely to toil, but even to grow weary, when the pains of

discovering are amply compensated by the pleasures of discovery. Eager

for novelty, we are wont to travel far into unknown countries, that with

our own eyes we may witness what we have heard reported as having been

seen by others, where, however, we for the most part find

---- minuit præsentia famam:

that the presence lessens the repute. It were disgraceful, therefore,

with this most spacious and admirable realm of nature before us, and

where the reward ever exceeds the promise, did we take the reports of

others upon trust, and go on coining crude problems out of these, and on

them hanging knotty and captious and petty disputations. Nature is

herself to be addressed; the paths she shows us are to be boldly

trodden; for thus, and whilst we consult our proper senses, from

inferior advancing to superior levels, shall we penetrate at length into

the heart of her mystery.

_Of the Manner and Order of acquiring Knowledge._

Although there is but one road to science, that to wit, in which we

proceed from things more known to things less known, from matters more

manifest to matters more obscure; and universals are principally known

to us, science springing by reasonings from universals to particulars;

still the comprehension of universals by the understanding is based upon

the perception of individual things by the senses. Both of Aristotle’s

propositions, therefore, are true: First, the one in his Physics,[122]

where he says, “The way is naturally prepared, from those things that

are more obvious and clear to us, to those things that are more obvious

and clear by nature. For, indeed, the same things are not both known to

us and extant simply: whence it is indispensable to proceed in this way,

viz. from those things that are of a more obscure nature, but to us are

more apparent, to those that are of a nature more obvious and distinct.

Now those things are, in the first instance, more perspicuous and

manifest to us that are most confused in fact; whence it is necessary to

proceed from universals to particulars; for the whole, according to the

dictates of sense, is the more obvious; and the universal is a certain

whole.” And again, that other in his Analytics,[123] where he thus

expresses himself: “Singulars are to us more known, and are the first

that exist according to the information of sense; for, indeed, there is

nothing in the understanding which was not first in the sense. And

although that reasoning is naturally prior and more known which proceeds

by syllogism, still is that more perspicuous to us which is based on

induction. And therefore do we more readily define singulars than

universals, for there is more of equivocation in universals: whence it

is advisable from singulars to pass to universals.”

All this agrees with what we have previously said, although at first

blush it may seem contradictory; inasmuch as universals are first

imbibed from particulars by the senses, and in so far are only known to

us as an universal is a certain whole and indistinct thing, and a whole

is known to us according to sense. For though in all knowledge we begin

from sense, because, as the philosopher quoted has it, sensible

particulars are better known to sense, still the sensation itself is an

universal thing. For, if you observe rightly, although in the external

sense the object perceived is singular, as, for example, the colour

which we call yellow in the eye, still when this impression comes to be

made an abstraction, and to be judged of and understood by the internal

sensorium, it is an universal. Whence it happens that several persons

abstract several species, and conceive different notions, from viewing

the same object at the same time. This is conspicuous among poets and

painters, who, although they contemplate one and the same object in the

same place at the same moment, and with all other circumstances

agreeing, nevertheless regard and describe it variously, and as each has

conceived or formed an idea of it in his imagination. In the same way,

the painter having a certain portrait to delineate, if he draw the

outline a thousand times, he will still give a different face, and each

not only differing from the other, but from the original countenance;

with such slight variety, however, that looking at them singly, you

shall conceive you have still the same portrait set before you,

although, when set side by side, you perceive how different they are.

Now the reason is this: that in vision, or the act of seeing itself,

each particular is clear and distinct; but the moment the object is

removed, as it is by merely shutting the eyes, when it becomes an

abstraction in the fancy, or is only retained in the memory, it appears

obscure and indistinct; neither is it any longer apprehended as a

particular, but as a something that is common and universal. Seneca[124]

explains this subtlety, according to Plato’s views, in very elegant

terms: “An idea,” he says, “is an eternal copy of the things that have

place in nature. I add an explanation of this definition, that the

matter may be made plainer to you. I desire to take your portrait; I

have you as the prototype of the picture, from which my mind takes a

certain impression which it transfers to the canvass. The countenance,

therefore, which teaches and directs me, and from which the imitation is

sought, is the idea.” A little farther on he proceeds: “I have but just

made use of the image which a painter forms in his mind, by way of

illustration. Now, if he would paint a likeness of Virgil, he forms an

intuitive image of his subject: the idea is the face of Virgil, the type

of his future work; and this which the artist conveys and transfers to

his work is the resemblance or portrait. What difference is there? you

ask: the one is the pattern or prototype, the other the form taken from

the pattern and fixed in the work; the artist imitates the one, he

creates the other. A statue has a certain expression of face; this is

the Eidos, the species or representation; the prototype himself has a

certain expression, which the statuary conceiving, transfers to his

statue: this is the idea. Do you desire yet another illustration of the

distinction? The Eidos is in the work; the idea without the work, and

not only without the work, but it even existed before the work was

begun.” For the things that have formerly been noted, and that by use or

wont have become firmly fixed in the mind of the artist, do, in fact,

constitute art and the artistic faculty; art, indeed, is the reason of

the work in the mind of the artist. On the same terms, therefore, as art

is attained to, is all knowledge and science acquired; for as art is a

habit with reference to things to be done, so is science a habit in

respect of things to be known: as that proceeds from the imitation of

types or forms, so this proceeds from the knowledge of natural things.

Each has its origin in sense and experience, and it is impossible that

there can rightly be either art or science without visible instance or

example. In both, that which we perceive in sensible objects differs

from the image itself which we retain in our imagination or memory. That

is the type, idea, forma informans; this is the imitation, the Eidos,

the abstract species. That is a thing natural, a real entity; this a

representation or similitude, and a thing of the reason. That is

occupied with the individual thing, and itself is single and particular;

this is a certain universal and common thing. That in the artist and man

of science is a sensible thing, clearer, more perfect; this a matter of

reason and more obscure: for things perceived by sense are more assured

and manifest than matters inferred by reason, inasmuch as the latter

proceed from and are illustrated by the former. Finally, sensible things

are of themselves and antecedent; things of intellect, however, are

consequent, and arise from the former, and, indeed, we can in no way

attain to them without the help of the others. And hence it is, that

without the due admonition of the senses, without frequent observation

and reiterated experiment, our mind goes astray after phantoms and

appearances. Diligent observation is therefore requisite in every

science, and the senses are frequently to be appealed to. 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; I appeal to your own eyes as my witnesses and

judge. For as all true science rests upon those principles which have

their origin in the operation of the senses, particular care is to be

taken that by repeated dissection the grounds of our present subject be

fully established. If we do otherwise, we shall but come to empty and

unstable opinions; solid and true science will escape us altogether:

just as commonly happens to those who form their notions of distant

countries and cities, or who pretend to get a knowledge of the parts of

the human body, from drawings and engravings, which but too frequently

present things under false and erroneous points of view. And so it is,

that in the present age we have an abundance of writers and pretenders

to knowledge, but very few who are really learned and philosophers.

Thus much have I thought good, gentle reader, to present to you, by way

of preface, that understanding the nature of the assistance to which I

have trusted, and the counsel by which I have been led in publishing

these my observations and experiments; and that you yourself in passing

over the same ground, may not merely be in a condition to judge between

Aristotle and Galen, but, quitting subtleties and fanciful conjectures,

embracing nature with your own eyes, that you may discover many things

unknown to others, and of great importance.

_Of the same matters, according to Aristotle._

There is no such thing as innate knowledge, according to Aristotle;

neither opinion, nor art, nor understanding, nor speech, nor reason

itself, inhere in us by nature and from our birth; but all of these, as

well as the qualities and habitudes, which are believed to be

spontaneous, and to lie under the control of our will, are to be

regarded as among the number of those things that reach us from without

according to nature: such as the virtues and the vices, for which men

are either praised and rewarded or reproved and punished. All our

knowledge, therefore, of every kind has to be acquired. But this is not

the place to inquire into the first principles of knowledge.

I believe, however, that it will not be useless if I premise a few words

as to whence and how our knowledge reaches us, both with a view to

rendering what I shall say on the subject of generation more readily

intelligible, and of removing any doubts that may arise out of this

opinion of the Stagirite,[125] who asserts that all doctrine and

discipline based on reason are derived from antecedent knowledge; whence

it seems to follow that there is either no first knowledge, or that this

must be innate, a conclusion which is in contradiction with what has

already been stated.

The doubt, however, is by and by resolved by Aristotle[126] himself,

when he treats of the mode in which knowledge is acquired: for after he

has taught that all certain knowledge is obtained through syllogism and

demonstration, and made it manifest that every demonstrative syllogism

proceeds from true and necessary first principles; he goes on to inquire

how principles become known, and what the faculty is that knows; at the

same time, too, he discusses the question, Whether habits, if not

innate, are engendered; and whether, being innate, they lie concealed?

“We have not,” he says, “these habits; for it happens that they are

concealed from those who acquire the most admirable kinds of knowledge

through demonstration. If, however, we receive them, not having had them

previously, how should we become informed, how learn from non-antecedent

knowledge? It is obvious, therefore, that they are neither possessed,

nor can they be engendered in the ignorant and those who are endowed

with no habit. Whence it is essential that some faculty be possessed,

not however any which were more excellent, more exquisite than they.

Now it seems a thing common to all animals, that they have a congenital

power of judging, which we call sense. Since sense is innate, then, the

things perceived by sense remain in some animals; in others they do not

remain. Those in whom they do not remain, however, have either no

knowledge at all, or at least none beyond the simple perception of the

things which do not remain; others, again, when they perceive, retain a

certain something in their soul. Now, as there are many animals of this

description, there is already a distinction between one animal and

another; and to this extent, that in some there is reason from the

memory of things; and in others there is none. Memory, therefore, as is

said, follows from sense; but from repeated recollection of the same

thing springs experience (for repeated acts of memory constitute a

single experience). From experience, however, or from the whole and

universal stored quietly in the mind, (one, to wit, in place of a

multitude--because in the whole crowd of particulars there is one and

the same universal,) is derived the principle of art and of science: of

art, if it belong to production (i. e. action); of science, if it belong

to that which is (i. e. the knowledge of entity). Consequently there are

neither any definite habits that are innate, nor any habits that are

formed from other and more known habits, but from sense.”

From which words of Aristotle it plainly appears by what order or method

any art or science is acquired, viz. The thing perceived by sense

remains; from the permanence of the thing perceived results memory; from

multiplied memory, experience; from experience, universal reason,

definitions, and maxims or common axioms, the most certain principles of

knowledge; for example, the same thing under like conditions cannot be

and not be; every affirmation or negation is either true or false; and

so on.

Wherefore, as we have said above, there is no perfect knowledge which

can be entitled ours, that is innate; none but what has been obtained

from experience, or derived in some way from our senses; all knowledge,

at all events, is examined by these, approved by them, and finally

presents itself to us firmly grounded upon some pre-existing knowledge

which we possessed: because without memory there is no experience, which

is nothing else than reiterated memory; in like manner memory cannot

exist without endurance of the things perceived, and the thing perceived

cannot remain where it has never been.

The supreme dictator in philosophy again and elsewhere expresses himself

very elegantly in the same direction:[127] “All men desire by nature to

know; the evidence of this is the pleasure they take in using their

senses, among which the sight is that which is particularly preferred,

because this especially serves us to acquire knowledge, and informs us

of the greatest number of differences. Nature, therefore, endowed

animals with sense; some of them, however, have no memory from the

operations of their senses; others, again, have memory; and this is the

reason wherefore some are more intelligent, and some more capable of

receiving instruction than others, those, namely, that want

recollection. Some show discretion independently of tuition: inasmuch as

there are many that do not hear, such as bees and others of the same

kind. But all animals which along with memory have the faculty of

hearing are susceptible of education. Other creatures, again, live

possessed of fancy and memory, but they have little store of experience;

the human kind, however, have both art and reasoning. Now experience

comes to man through memory; for many memories of the same thing have

the force of a single experience: so that experience appears to be

almost identical with certain kinds of art and science;[128] and,

indeed, men acquire both art and science by experience: for experience,

as Polus rightly remarks, begets art, inexperience is waited on by

accident.”

By this he plainly tells us that no one can truly be entitled discreet

or well-informed, who does not of his own experience, i. e. from

repeated memory, frequent perception by sense, and diligent observation,

know that a thing is so in fact. Without these, indeed, we only imagine

or believe, and such knowledge is rather to be accounted as belonging to

others than to us. The method of investigating truth commonly pursued at

this time therefore is to be held as erroneous and almost foolish, in

which so many inquire what others have said, and omit to ask whether the

things themselves be actually so or not; and single universal

conclusions being deduced from several premises, and analogies being

thence shaped out, we have frequently mere verisimilitudes handed down

to us instead of positive truths. Whence it comes that pretenders to

knowledge and sophists, trimming up the discoveries of others, changing

the arrangement only, or the language, and adding a few things of no

importance, audaciously send them forth as their own, and so render

philosophy, which ought to be certain and perspicuous, obscure and

intricate. For he who reads the words of an author and fails, through

his own senses, to obtain images of the things that are conveyed in

these words, derives not true ideas, but false fancies and empty

visions; whence he conjures up shadows and chimeras, and his whole

theory or contemplation, which, however, he regards as knowledge, is

nothing more than a waking dream, or such a delirium as the sick fancy

engenders.

I therefore whisper in your ear, friendly reader, and recommend you to

weigh carefully in the balance of exact experience all that I shall

deliver in these Exercises on the Generation of Animals; I would not

that you gave credit to aught they contain save in so far as you find it

confirmed and borne out by the unquestionable testimony of your own

senses.

The same course is even advised by Aristotle, who, after having gone

over a great many particulars about bees, says at length:[129] “That

the generation of bees takes place in this way appears both from reason

and from those things that are seen to occur in their kind. Still all

the incidents have not yet been sufficiently examined. And when the

investigation shall be complete, then will sense be rather to be trusted

than reason; reason, however, will also deserve credit, if the things

demonstrated accord with the things that are perceived by sense.”

_Of the Method to be pursued in studying Generation._

Since in Animal Generation, (and, indeed, in all other subjects upon

which information is desired,) inquiry must be begun from the causes,

especially the material and efficient ones, it appears advisable to me

to look back from the perfect animal, and to inquire by what process it

has arisen and grown to maturity, to retrace our steps, as it were, from

the goal to the starting place; so that when at last we can retreat no

further, we shall feel assured that we have attained to the principles;

at the same time we shall perceive from what primary matter, and from

what efficient principle, and in what way from these the plastic force

proceeds; as also what processes nature brings into play in the work.

For primary and more remote matter, by abstraction and negation (being

stripped of its garments as it were) becomes more conspicuous; and

whatever is first formed or exists primarily in generation, is the

material cause of everything that succeeds. For example, before a man

attains to maturity, he was a boy, an infant, an embryo. And then it is

indispensable to inquire further as to what he was in his mother’s womb

before he was an embryo or fœtus; whether made up of three bubbles, or a

shapeless mass, or a conception or coagulum proceeding from the mingled

seminal fluids of his parents, or what else, as we have it delivered to

us by writers. In like manner, before a fowl had attained to maturity or

perfection,--because capable of engendering its like,--it was a chicken;

previous to which it was an embryo or fœtus in the egg; and before this,

Hieronymus Fabricius, of Aquapendente, has observed rudiments of the

head, eyes, and spine. But when he asserts that the bones are formed

before the muscles, heart, liver, lungs, and precordial parts, and

contends that all the internal organs must exist before the external

ones, he follows probabilities according to previous notions rather than

inspection; and quitting the evidences of sense that rest on anatomy, he

seeks refuge in reasonings upon mechanical principles; a procedure that

is anything but becoming in a great anatomist, whose duty it was

faithfully to narrate the changes he observed taking place day by day in

the egg, up to the period when the fœtus is perfected; and this the

rather as he expressly proposed to himself to write the history of the

formation of the chick in the egg, and to exhibit in figures what

happens in the course of each successive day. It would have been in

harmony with such a design, I say, had we been informed, on the

testimony of the senses, of what parts are formed first, together, or

subsequently in the egg; and not had mere opinions or musty conjectures,

and the instances of houses and ships, adduced in illustration of the

order and mode of formation of the parts.

We, therefore, in conformity with the method proposed, shall show in the

first place in the egg, and then in the conceptions of other animals,

what parts are first, and what are subsequently formed by the great God

of Nature with inimitable providence and intelligence, and most

admirable order. Next we shall inquire into the primary matter out of

which, and the efficient cause by which generation is accomplished, and

also the order and economy of generation, as observed by us; that from

thence, from its own work, we may have some certain information of the

several faculties of the formative and vegetative soul, and of the

nature of the soul itself, judging from its members or organs, and their

functions.

This, indeed, cannot be done in all animals: first, because a sufficient

number of several of these cannot be commanded; and again, because, from

the small size of many, they escape our powers of vision. It must

suffice, therefore, that this is done in some kinds which are more

familiarly known to us, and that we refer all the rest to these as types

or standards.

We have, therefore, selected those that may tend to render our

experiments more undeniable, viz. the larger and more perfect animals,

and that are easily within reach. For in the larger animals all things

are more conspicuous; in the more perfect, they are also more distinct;

and in those that we can command, and that live with us, everything is

more readily examined: we have it in our power so often as we please to

repeat our observations, and so to free them from all uncertainty and

doubt. Now, among oviparous animals of this description, we have the

common fowl, the goose, duck, pigeon; and then we have frogs, and

serpents, and fishes; crustacea, testacea, and mollusca; among insects,

bees, wasps, butterflies, and silkworms; among viviparous creatures, we

have sheep, goats, dogs, cats, deer, and oxen; lastly, we have the most

perfect of all animals, man.

Having studied and made ourselves familiar with these, we may turn to

the consideration of the more abstruse nature of the vegetative soul,

and feel ourselves in a condition to understand the method, order, and

causes of generation in animals generally; for all animals resemble one

or other of those above mentioned, and agree with them either generally

or specifically, and are procreated in the same manner, or the mode of

their generation at least is referrible by analogy to that of one or

other of them. For Nature, perfect and divine, is ever in the same

things harmonious with herself, and as her works either agree or differ,

(viz. in genus, species, or some other proportion,) so is her agency in

these (viz. generation or development) either the same or diverse. He

who enters on this new and untrodden path, and out of the vast realm of

Nature endeavours to find the truth by means of anatomical dissections

and experiments, is met by such a multitude of facts, and these of so

unusual an aspect, that he may find it more difficult to explain and

describe to others the things he has seen, than he reckoned it labour to

make his observations; so many things are encountered that require

naming; such is the abundance of matter and the dearth of words. But if

he would have recourse to metaphors, and by means of old and familiar

terms would make known his ideas concerning the things he has newly

discovered, the reader would have little chance of understanding him

better than if they were riddles that were propounded; and of the thing

itself, which he had never seen, he could have no conception. But then,

to have recourse to new and unusual terms were less to bring a torch to

lighten, than to darken things still more with a cloud: it were to

attempt an explanation of a matter unknown by one still more unknown,

and to impose a greater toil on the reader to understand the meaning of

words than to comprehend the things themselves. And so it happens that

Aristotle is believed by the inexperienced to be obscure in many places;

and on this account, perhaps, Fabricius of Aquapendente rather intended

to exhibit the chick in ovo in his figures than to explain its formation

in words.

Wherefore, courteous reader, be not displeased with me, if, in

illustrating the history of the egg, and in my account of the generation

of the chick, I follow a new plan, and occasionally have recourse to

unusual language. Think me not eager for vainglorious fame rather than

anxious to lay before you observations that are true, and that are

derived immediately from the nature of things. That you may not do me

this injustice, I would have you know that I tread in the footsteps of

those who have already thrown a light upon this subject, and that,

wherever I can, I make use of their words. And foremost of all among the

ancients I follow Aristotle; among the moderns, Fabricius of

Aquapendente; the former as my leader, the latter as my informant of the

way. For even as they who discover new lands, and first set foot on

foreign shores, are wont to give them new names which mostly descend to

posterity, so also do the discoverers of things and the earliest writers

with perfect propriety give names to their discoveries. And now I seem

to hear Galen admonishing us, that we should but agree about the things,

and not dispute greatly about the words.

ON

ANIMAL GENERATION.

EXERCISE THE FIRST.

_Wherefore we begin with the history of the hen’s egg._

Hieronymus Fabricius of Aquapendente, (whom, as I have said, I have

chosen my informant of the way I am to follow,) in the beginning of his

book on the Formation of the Ovum and Chick, has these words: “My

purpose is to treat of the formation of the fœtus in every animal,

setting out from that which proceeds from the egg: for this ought to

take precedence of all discussion of the subject, both because from this

it is not difficult to make out Aristotle’s views of the matter, and

because his treatise on the Formation of the Fœtus from the egg, is by

far the fullest, and the subject is by much the most extensive and

difficult.”

We, however, commence with the history of the hen’s egg as well for the

reasons above assigned, as because we can thence obtain certain data

which, as more familiar to us, will serve to throw light on the

generation of other animals; for as eggs cost little, and are always to

be had, we have an opportunity from them of observing the first clear

and unquestionable commencements of generation, how nature proceeds in

the process, and with what admirable foresight she governs every part of

the work.

Fabricius proceeds: “Now that the contemplation of the formation of the

chick from the egg is of very ample scope, appears from this, that the

greater number of animals are produced from ova. Passing by almost all

insects and the whole of the less perfect animals, which are obviously

produced from eggs, the greater number of the more perfect are also

engendered from eggs.” And then he goes on to particularize: “All

feathered creatures; fishes likewise, with the single exception of the

whale tribes; crustacea, testacea, and all mollusca; among land animals,

reptiles, millepeds, and all creeping things; and among quadrupeds, the

entire tribe of lizards.”

We, however, maintain (and shall take care to show that it is so), that

all animals whatsoever, even the viviparous, and man himself not

excepted, are produced from ova; that the first conception, from which

the fœtus proceeds in all, is an ovum of one description or another, as

well as the seeds of all kinds of plants. Empedocles,[130] therefore,

spoke not improperly of the _oviparum genus arboreum_, “the egg-bearing

race of trees.” The history of the egg is therefore of the widest scope,

inasmuch as it illustrates generation of every description.

We shall, therefore, begin by showing where, whence, and how eggs are

produced; and then inquire by what means and order and successive steps

the fœtus or chick is formed and perfected in and from the egg.

Fabricius has these additional words: “The fœtus of animals is

engendered in one case from an ovum, in another from the seminal fluid,

in a third from putrefaction; whence some creatures are oviparous,

others viviparous, and yet others, born of putrefaction or by the

spontaneous act of nature, automatically.”

Such a division as this, however, does not satisfy me, inasmuch as all

animals whatsoever may be said in a certain sense to spring from ova,

and in another certain sense from seminal fluid; and they are entitled

oviparous, viviparous, or vermiparous, rather in respect of their mode

of bringing forth than of their first formation. Even the creatures that

arise spontaneously are called automatic, not because they spring from

putrefaction, but because they have their origin from accident, the

spontaneous act of nature, and are equivocally engendered, as it is

said, proceeding from parents unlike themselves. And, then, certain

other animals bring forth an egg or a worm as their conception and

semen, from which, after it has been exposed abroad, a fœtus is

produced; whence such animals are called oviparous or vermiparous.

Viviparous animals are so entitled because they retain and cherish their

conception in their interior, until from thence the fœtus comes forth

into the light completely formed and alive.

EXERCISE THE SECOND.

_Of the seat of generation._

“Nature,” says Fabricius, “was first solicitous about the place [where

generation should proceed], which she determined should be either within

or without the animal: within she ordained the uterus; without, the

ovum: in the uterus the blood and seminal fluid engendering; in the

ovum, however, the fluids or elements of which it consists supplying

pabulum for the production of the fœtus.”

Now, whatever is procreated of the semen properly so called originates

and is perfected either in the same place or in different places. All

viviparous creatures derive their origin and have their completion in

the uterus itself; but oviparous animals, as they have their beginning

within their parents, and there become ova, so is it beyond their

parents that they are perfected into the fœtal state. Among oviparous

animals, however, there are some that retain their ova till such time as

they are mature and perfect; such as all the feathered tribes, reptiles

and serpents. Others, again, extrude their semina in a state still

immature and imperfect, and it is without the body of the parent that

increase, maturity, and perfection, are attained. Under this head we

range frogs, many kinds of fishes, crustaceous, molluscous, and

testaceous animals, the ova of which, when first extruded, are but

beginnings, sketches, yelks which afterwards surround themselves with

whites, and attracting, concocting, and attaching nutriment to

themselves, are changed into perfect seeds or eggs. Such also are the

semina of insects (called worms by Aristotle), which, imperfect on their

extrusion and in the beginning, seek food for themselves, upon which

they are nourished, and grow from a grub into a chrysalis: from an

imperfect into a perfect egg or seed. Birds, however, and the rest of

the oviparous tribes, lay perfect eggs; whence without the uterus the

fœtus is engendered. And it was on this account that Fabricius admitted

two seats of generation: one internal, the uterus; another external, the

ovum. But he would have had more reason, in my opinion, had he called

the nest, or place where the eggs are laid, the external seat, that, to

wit, in which the extruded seed or egg is cherished, matured, and

perfected into a fœtus; for it is from the differences of this seat that

the generation of oviparous animals is principally distinguished. And it

is, indeed, a thing most worthy of admiration to see these creatures

selecting and preparing their nests with so much foresight, and

fashioning, and furnishing, and concealing them with such inimitable art

and ingenuity; so that it seems imperative on us to admit in them a

certain spark of the divine flame (as the poet said of bees); and,

indeed, we can more readily admire than imitate their untaught art and

sapience.

EXERCISE THE THIRD.

_Of the upper part of the hen’s uterus, or the ovary._

The uterus of the fowl is divided by Fabricius into the superior and

inferior portions, and the superior portion he calls the ovary.

The ovary is situated immediately beneath the liver, close to the spine,

over the descending aorta. In this situation, in the larger animals with

red blood, the cœliac artery enters the mesentery, at the origin,

namely, of the emulgent veins, or a little lower; in the situation

moreover in which in the other red-blooded and viviparous animals the

vasa præparantia, tending to the testes, take their origin: in the same

place at which the testes of the cock-bird are situated, there is the

ovary of the hen discovered. For some animals carry their testicles

externally; others have them within the body, in the loins, in the space

midway from the origins of the vasa præparantia. But the cock has his

testicles at the very origin of these vessels, as if his spermatic fluid

needed no preparation.

Aristotle[131] says that the ovum begins at the diaphragm; “I, however,”

says Fabricius, “in my treatise on Respiration, have denied that the

feathered kinds have any diaphragm. The difficulty is resolved by

admitting that birds are not entirely destitute of a kind of diaphragm,

inasmuch as they have a delicate membrane in the place of this septum,

which Aristotle calls a cincture and septum. Still they have no

diaphragm that is muscular, and that might aid respiration, like other

animals. But, indeed, Aristotle did not know the muscles.”

Thus is the prince of philosophers accused and excused in the same

breath, his challenger being himself not free from error; because it is

certain that Aristotle both knew the muscles, as I have elsewhere shown,

and the membranes, which in birds are not only situated transversely in

the direction of the cincture of the body, but extended in the line of

the longitudinal direction of the belly, supplying the place of the

diaphragm [of quadrupeds] and being subservient to respiration, as I

have shown in the clearest manner in my disquisitions on the Respiration

of Animals. And, passing over other particulars at this time, I shall

only direct attention to the fact, that birds breathe with great

freedom, and in singing also modulate their voice in the most admirable

manner, their lungs all the while being so closely connected with their

sides and ribs, that they can neither be dilated and rise, nor suffer

contraction in any considerable degree.

The bronchia or ends of the trachea in birds, moreover, are perforate,

and open into the abdomen (and this is an observation which I do not

remember to have met with elsewhere), so that the air inspired is

received into and stored up within the cells or cavities formed by the

membranes mentioned above. In the same manner as fishes and serpents

draw air into ample bladders situated in the abdomen, and there store it

up, by which they are thought to swim more lightly; and as frogs and

toads, when in the height of summer they respire more vigorously assume

more than the usual quantity of air into their vesicular lungs, (whence

they acquire so large a size,) which they afterwards freely expire,

croaking all the while; so in the feathered tribes are the lungs rather

the route and passage for respiration than its adequate instrument.

Now, had Fabricius seen this, he would never have denied that these

membranes (with the assistance of the abdominal muscles at all events,)

could subserve respiration and perform the office of the diaphragm,

which, indeed, of itself, and without the assistance of the abdominal

muscles, were incompetent to act as an instrument of respiration. And,

then, the diaphragm has another duty to perform in those creatures in

whom it is muscular or fleshy, viz., to depress the stomach filled with

food, and the intestines distended with flatus, so that the heart and

lungs shall not be invaded, and life itself oppressed in its citadel.

But as there was no danger of anything of this kind in birds, they have

a membranous septum, perfectly well adapted to the purposes of

respiration, so that they have very properly been said to have a

diaphragm. And were birds even entirely without anything in the shape of

a diaphragm, still would Aristotle not be liable to criticism for

speaking of the ova commencing at the septum transversum, because by

this title he merely indicates the place where the diaphragm is usually

met with in other animals. In the same way we ourselves say that the

ovary is situated at the origin of the spermatic vasa præparantia,

although the hen has, in fact, no such vessels.

The perforations of the lungs discovered by me (and to which I merely

direct attention in this place,) are neither obscure nor doubtful, but,

in birds especially, sufficiently conspicuous, so that in the ostrich I

found many conduits which readily admitted the points of my fingers. In

the turkey, fowl, and, indeed, almost all birds, you will find that a

probe passed downwards by the trachea makes its way out of the lungs,

and is discovered lying naked and exposed in one or another of the

abdominal cells. Air blown into the lungs of these creatures with a pair

of bellows passes on with a certain force even into the most inferior of

these cells.

We may even be permitted to ask, whether in man, whilst he lives, there

is not a passage from openings of the same kind into the cavity of the

thorax? For how else should the pus poured out in empyema and the blood

extravasated in pleurisy make its escape? In penetrating wounds of the

chest, the lungs themselves being uninjured, air often escapes by the

wound; or liquids thrown into the cavity of the thorax, are discharged

with the expectoration. But our views of this subject will be found

fully expressed elsewhere, viz., in our disquisitions on the Causes,

Uses, and Organs of Respiration.

I return to the ovary and the upper portion of the fowl’s uterus, in

which the rudiments of the eggs are produced. These, according to

Aristotle,[132] in the first instance are small, and of a white colour;

growing larger, they subsequently become of a paler and then of a deeper

yellow.

The superior uterus of Fabricius, however, has no existence until after

the hen has conceived, and contains the rudiments of ova within it; when

it may be designated as a cluster of papulæ. And he therefore observes

very properly, “The superior uterus is nothing more than an almost

infinite congeries of yelks, which appear collected as it were into a

single cluster, of a rounded form, and of every size, from that of a

grain of mustard to that almost of a walnut or medlar. This multitude of

vitelli is aggregated and conjoined very much in the manner of a bunch

of grapes, for which reason I shall constantly speak of it as the

vitellarium or raceme of yelks; a comparison which Aristotle himself

made in speaking of the soft or scaleless fishes, when he says,[133]

their ovary or roe is extruded agglutinated into a kind of raceme or

bunch of grapes. And in the same way as in a bunch of grapes the several

berries are seen to be of different sizes, some large, some small, some

of very diminutive proportions, each hanging by its several peduncle, so

do we find precisely the same thing in the vitellarium of the fowl.”

In fishes, frogs, crustacea, and testacea, however, matters are

otherwise arranged. The ovary or vitellary here contains ova of one

uniform size only, which being extruded increase, attain maturity, and

give birth to fœtuses simultaneously. But in the ovary of the common

fowl, and almost all the rest of the oviparous tribes, the yelks are

found in various stages of their growth, from dimensions that are

scarcely visible up to the full size. Nevertheless the eggs of the fowl

and other birds, (not otherwise than in those cases where the eggs are

all engendered and laid at the same moment,) ripen their fœtuses under

the influence of incubation in the same nest, and produce them perfect,

nearly at the same time. In the family of the pigeons, however, (which

lay and incubate no more than two eggs in the same nest,) I have

observed that all the ova crowded together in the ovary, with the

exception of a single pair, were of the same dimensions; this pair was

very much larger than any of the others, and already prepared to descend

into the second or lower uterus. In these creatures, therefore, the

number of young is great, not because of the multitude produced at a

time, but of the frequency with which births take place, viz., every

month. In the same way, among cartilaginous fishes, such as the skates,

dog-fishes, &c., two eggs only come to maturity together, one of which

descends from the right the other from the left corner of the uterus

into the inferior portion, where they are cherished, and where they

finally produce living fœtuses, precisely as happens among viviparous

animals; in the ovary, nevertheless, there is almost infinite store of

ova of various sizes--in the ray I have counted upwards of a hundred.

The ova of the other oviparous tribes are either perfected externally,

as in the case of fishes, or they are concocted or matured, as in the

instance of testacea, crustacea, and spiders. Testaceous animals lay

their eggs amidst froth; the crustaceous tribes, such as the shrimp,

crab, and lobster, bear them about with them, attached to certain

appendages; and the spiders carry them about and cherish them, laid up

in a kind of purse or basket, made of their web. The beetle rolls its

eggs in dung, using its hind legs in the operation, and buries them.

Now, in all these creatures the quantity of eggs is almost incredibly

great: in fishes they form two oblong bladders or follicles, as may be

seen in the carp, herring, and smelt, in all of which, as there is no

uterus, but merely an ovary present, so is this sometimes crowded with

ova to such a degree, that it comes to surpass the body in bulk.

Of such ovaries of the mullet and carp, salted and pressed, and dried in

the smoke, was prepared that article of food in such request among the

Greeks and old Italians, (called botorcha by the latter, ώά τάριχα, i.

e. salted eggs, by the former,) and very similar, we may presume, to the

masses which we find in the insides of our smoked herrings, and to the

compact granular red-coloured roe of our lobsters. The article prepared

from the salted roe of the sturgeon, which is called caviare, and

resembles black soap, is still the delight of epicures.

In those fishes that are highly prolific such a quantity of eggs is

engendered, that the whole abdomen can scarcely contain them, even when

they are first produced, still less when they have grown to any size.

In fishes, therefore, there is no part save the ovary dedicated to

purposes of reproduction. The ova of these animals continue to grow

without the body, and do not require the protection of an uterus for

their evolution. And the ovary here appears to bear an analogy to the

testicles or vesiculæ seminales, not only because it is found in the

same place as the testes in the male, (the testes in the cock being

situated, as we have said, close to the origin of the cœliac artery,

near the waist, in the very same place as the ovary in the hen,) but

because among fishes, in both sexes, as the time of spawning approaches,

two follicles, alike in situation, size, and shape, are discovered,

extending the whole length of the abdomen; which increase and become

distended at the same period: in the male with a homogeneous milky

spermatic matter, (whence the term milk or milt of fishes;) in the

female with innumerable granules, which, from their diminutive size and

close texture, in the beginning of the season, escape the powers of

vision, and present themselves as constituting an uniform body, bearing

the strongest resemblance to the milt of the male regularly coagulated.

By and by they are seen in the guise of minute grains of sand, adhering

together within their follicles.

In the smaller birds that lay but once a year, and a few eggs only, you

will scarcely discover any ovary. Still, in the place where the

testicles are situated in the male, there in the female, and not less

obviously than the testicles of the male, you will perceive three or

four vesicles (the number being in proportion to that of the eggs of

which they are the rudiments), by way of ovary.

In the cornua of the uterus of snakes (which resemble the vasa

deferentia in male animals), the first rudiments of the ova present

themselves as globules strung upon a thread, in the same way as women’s

bracelets, or like a rosary composed of amber beads.

Those ova that are found in the ovary of the fowl consequently are not

to be regarded as perfect eggs, but only as their rudiments; and they

are so arranged on the cluster, they succeed each other in such an order

and of such dimensions, that they are always ready for each day’s

laying. But none of the eggs in the ovary are surrounded with albumen;

there the yelk exists alone, and each, as it enlarges, extricates itself

from the general congeries of smaller ones, in order that it may the

more readily find space to grow. Fabricius, therefore, is right when he

says,[134] “The yelks which are on the surface of the cluster are larger

than those of the middle, which are surrounded as it were by the larger

ones. The very smallest of all the ova are situated towards the centre.”

That is to say, those that grow acquire larger dimensions and become

detached from the rest, and as this proceeds, the several yelks, besides

their tunica propria, are invested with another from the ovary, which

embraces them externally, and connects them with the base whence they

spring. This coat is, therefore, entitled the peduncle by Fabricius, and

its office is that of a foot-stalk, viz. to supply nourishment to the

ovum, in the same way as fruit is nourished through the stalk by which

it is connected with the tree. For this peduncle is a hollow membranous

bond of union, extending from the foundation of the cluster [the stroma

of the ovary] to the yelk, coming into contact with which, it is dilated

and expanded in the same way as the optic nerve in the eye, and covers

the vitellus with an external tunic. This perchance was what Aristotle

called the στόλον ὸμφαλοώδην, or umbilical appendix, and described as

forming a kind of tube. This peduncle includes numerous vessels, which

are distributed on all sides around the yelk.

So much is accurately related by Fabricius; but he errs when he says,

“This tunic does not surround the entire vitellus, but only extends upon

it a little beyond the middle, very much in the manner of an acorn

within its cup; whence it comes that the outer portion of the yelk,

which is not invested by the membrane in question, presents itself free

from vessels, and to appearance naked.” The membrane, nevertheless,

surrounds the yelk completely; but on the outer aspect it is not very

easily distinguished from the tunica propria, both of them being of

extreme delicacy. Posteriorly, however, and where the yelk is turned

towards the basis of the cluster, the tunic in question does not adhere

to the vitellus, neither does it send any vessels to this part, but

merely embraces it in the manner of a sac.

Each vitellus receives a distinct tunic from the ovarian basis; whence

this is not to be regarded as the common uterus, since nothing is

discovered here except the cluster or heap of ova, of many different

sizes, proceeding from the same foundation.

Now, this foundation or basis is a body sui generis, arising on the

spine of the feathered kinds, connected by means of large arteries and

veins, and of a loose, porous, and spongy texture, in order that

multitudes of ova may be produced from it, and that it may supply tunics

to all; which tunics, when the yelks have grown to their full size, are

distended by them, and then the tunics surround the vitelli, in the

manner of sacks with narrower necks and more capacious bellies, very

much like the flasks that are formed by the breath of the glass-blower.

Fabricius then proceeds: “The yelks, as they proceed from small

beginnings, from the size of millet or mustard seeds, and are at first

not only extremely small, but colourless, as Aristotle says, so do they

increase by degrees, and, according to Aristotle, become first of a

paler and then of a deeper yellow, until they have attained to the

dimensions familiar to all.” I, however, have observed ova vastly

smaller than millet seeds, ova which, like papulæ or sudamina, or the

finest grains of sand, (such as we have indicated as found in the roe of

fishes,) almost escaped the powers of sight; their places, indeed, were

only proclaimed by a kind of roughness of the membranes.

EXERCISE THE FOURTH.

_Of the infundibulum._

The next succeeding portion of the uterus of the common fowl is called

the infundibulum by Fabricius. It forms a kind of funnel or tube,

extending downwards from the ovary, (which it everywhere embraces,) and

becoming gradually wider, terminates in the superior produced portion of

the uterus. This infundibulum yields a passage to the yelks when they

have broken from their foot-stalks in their descent from the ovary into

the second uterus (so it is styled by Fabricius). It resembles the

tunica vaginalis in the scrotum, and is a most delicate membrane, very

easily dilatable, fitted to receive the yelks that are daily cast loose,

and to transmit them to the uterus mentioned.

Would you have an example of these structures? Figure to yourself a

small plant, whose tuberous roots should represent the congeries of

yelks; its stalk the infundibulum. Now, as the stalk of this plant dies

in the winter and disappears, in like manner, when the fowl ceases to

lay eggs, the whole ovary, with the infundibulum, withers, shrinks, and

is annulled; the basis [stroma] and indication of the roots being still

left.

This infundibulum seems only to discharge the office of a conduit, or

tube of passage: the yelk is never observed sticking in it; but as the

testes at times creep upwards through the tunicæ vaginales into the

groins, and in some animals--the hare and the mole--even become

concealed within the abdomen, and nevertheless again descend and show

themselves externally, so are the vitelli transmitted through the

infundibulum from the ovary into the uterus. Its office is served, and

even its form is imitated, by the funnel which we make use of when we

pour fluids from one vessel into another having a narrower mouth.

EXERCISE THE FIFTH.

_Of the external portion of the uterus of the common fowl._

Fabricius pursues his account of the uterus after having described the

ovary, and in such an inverse order, that he premises a description of

the superior portion or appendage of the uterus before he approaches the

uterus itself. He assigns to it three turns or spirals, with somewhat

too much of precision or determinateness, and settles the respective

situations of these spirals, which are nevertheless of uncertain seat.

Here, too, he very unnecessarily repeats his definition of the

infundibulum. I would, therefore, in this place, beg to be allowed to

give my own account of the uterus of the fowl, according to the

anatomical method, which I consider the more convenient, and proceeding

from external to internal parts, in opposition to the method of

Fabricius.

In the fowl stripped of its feathers, the fundament will be observed not

contracted circularly, as in other animals, but forming a depressed

orifice, slit transversely, and consisting of two lips lying over

against each other, the superior of the two covering and concealing the

inferior, which is puckered together. The superior labium, or velabrum,

as it is called, arises from the root of the rump, and as the upper

eyelid covers the eye, so does this cover the three orifices of the

pudenda, viz. the anus, the uterus, and the ureters, which lie concealed

under the velabrum as under a kind of prepuce; very much as in the

pudenda of the woman we have the orifice of the vulva and the meatus

urinarius concealed between the labia and the nymphæ. So that without

the use of the knife, or a somewhat forcible retraction of the velabrum

in the fowl, neither the orifice by which the fæces pass from the

intestines, nor that by which the urine issues from the ureters, nor yet

that by which the egg escapes from the uterus, can be perceived. And as

the two excrementitious discharges (the urine and the fæces) are

expelled together as from a common cloaca, the velabrum being raised at

the time, and the respective outlets exposed; so, during intercourse,

the hen on the approach of the cock uncovers the vulva, and prepares for

his reception, a circumstance observed by Fabricius in the turkey hen

when she is eager for the male. I have myself observed a female ostrich,

when her attendant gently scratched her back, which seemed to excite the

sexual appetite, to lie down on the ground, lift up the velabrum, and

exhibit and protrude the vulva, seeing which the male, straightway

inflamed with a like œstrum, mounted, one foot being kept firm on the

ground, the other set upon the back of the prostrate female; the immense

penis (you might imagine it a neat’s tongue!) vibrated backwards and

forwards, and the process of intercourse was accompanied with much ado

in murmuring and noise--the heads of the creatures being at the same

time frequently thrust out and retracted--and other indications of

enjoyment. Nor is it peculiar to birds, but common to animals at large,

that, wagging the tail and protruding the genital parts, they prepare

for the access of the male. And, indeed, the tail in the majority of

animals has almost the same office as the velabrum in the common fowl;

unless it were raised or drawn aside, it would interfere with the

discharge of the fæces and the access of the male.

In the female red-deer, fallow-deer, roe, and others of the more

temperate animals, there is a corresponding protection to their private

parts, a membranous velabrum covering the vulva and meatus urinarius,

which must be raised before the penis of the male can be introduced.

In animals that have a tail, moreover, parturition could not take place

unless this part were lifted up; and even the human female is assisted

in her labour by having the coccyx anointed and drawn outwards with the

finger.

A surgeon, a trustworthy man, and with whom I am upon intimate terms, on

his return from the East Indies informed me, in perfect sincerity, that

some inland and mountainous parts of the island of Borneo are still

inhabited by a race of caudate human beings (a circumstance of which we

also read in Pausanias), one of whom, a virgin, who had only been

captured with great difficulty, for they live in the woods, he himself

had seen, with a tail, thick, fleshy, and a span in length, reflected

between the buttocks, and covering the anus and pudenda: so regularly

has nature willed to cover these parts.

To return. The structure of the velabrum in the fowl is like that of the

upper eyelid; that is to say, it is a fleshy and muscular fold of the

skin, having fibres extending from the circumference on every side

towards the centre; its inner surface, like that of the eyelid and

prepuce, being soft. Along its margin also there is a semicircular

tarsus, after the manner of that of the eyelid; and in addition, between

the skin and fleshy membrane, an interposed cartilage, extending from

the root of the rump, the sickle-shaped tarsus being connected with it

at right angles, (very much as we observe a small tail comprehended

between the wing on either side, in bats). By this structure the

velabrum is enabled more readily to open and close the foramina pudendi

that have been mentioned.

The velabrum being now raised and removed, certain foramina are brought

into view, some of which are very distinct, others more obscure. The

more obvious are the anus and vulva, or the outlet of the fæcal matters

and the inlet to the uterus. The more obscure are, first, that by which

the urine is excreted from the kidneys, and, second, the small orifice

discovered by Fabricius, “into which,” he says, “the cock immits the

spermatic fluid,” a foramen, however, which neither Antony Ulm, a

careful dissector, has indicated in Aldrovandus, nor any one else except

Fabricius, so far as I know, has ever observed.

All these foramina are so close to one another that they seem almost to

meet in a single cavity, which, as being common to the fæces and urine,

may be called the cloaca. In this cavity, the urine, as it descends from

the kidneys, is mingled with the feculent matters of the bowels, and the

two are discharged together. Through this, too, the egg, as it is laid,

forces itself a passage.

Now, the arrangements in this cavity are such, that both excrements

descending into a common sac, the urine is made use of as a natural

clyster for their evacuation. The cloaca is therefore thicker and more

rugous than the intestine; and at the moment of laying and of coition,

it is everted, (the velabrum which covers it being raised as I have

already said,) the lower portion of the bowel being as it were

prolapsed. At this moment all the foramina that terminate in the cloaca

are conspicuous; on the return or reduction of the prolapsed portion,

however, they are concealed, being all collected together as it were

into the common purse or pouch.

The more conspicuous foramina, those, viz. of the anus and uterus, are

situated, with reference to one another, differently in birds from what

they are in other animals. In these the pudendum, or female genital

part, is situated anteriorly between the rectum and bladder; in birds,

however, the excrementitious outlet is placed anteriorly, so that the

inlet to the uterus is situated between this and the rump.

The foramen, into which Fabricius believes the cock to inject his fluid,

is discovered between the orifice of the vulva and the rump. I, however,

deny any such use to this foramen; for in young chickens it is scarcely

to be seen, and in adults it is present indifferently both in males and

females. It is obvious, therefore, that it is both an extremely small

and obscure orifice, and can have no such important function to perform:

it will scarcely admit a fine needle or a bristle, and it ends in a

blind cavity; neither have I ever been able to discover any spermatic

fluid within it, although Fabricius asserts that this fluid is stored up

there even for a whole year, and that all the eggs contained in the

ovary may be thence fecundated, as it is afterwards stated.

All birds, serpents, oviparous quadrupeds, and likewise fishes, as may

readily be seen in the carp, have kidneys and ureters through which the

urine distils, a fact which was unknown to Aristotle and philosophers up

to this time. In birds and serpents, which have spongy or largely

vesicular lungs, the quantity of urine secreted is small, because they

drink little, and that by sipping; there was, therefore, no occasion for

an urinary bladder in these creatures: the renal secretion, as already

stated, is accumulated in a common cavity or cloaca, along with the

drier intestinal excrement. Nevertheless, I do find an urinary bladder

in the carp and some other fishes.

In the common fowl the ureters descend from the kidneys, which are

situated in long and ample cavities on either side of the back, to

terminate in the common cavity or cloaca. Their terminations, however,

are so obscure and so hidden by the margin of the cavity, that to

discover them from without and pass a fine probe into them would be

found impossible. Nor is this at all surprising, because in all, even

the largest animals, the insertion of the ureters near the neck of the

bladder is so tortuous and obscure, that although the urine distils

freely from them into the bladder, and calculi even make their way out

of them, still neither fluids nor air can be made to enter them by the

use of any amount of force. On the other hand, in birds as well as other

animals, a probe or a bristle passed downwards from the kidney towards

the bladder by the ureters, readily makes its way into the cloaca or

bladder.

These facts are particularly distinct in the ostrich, in which, besides

the external orifice of the common cavity which the velabrum covers, I

find another within the anus, having a round and constricted orifice,

shutting in some sort in the manner of a sphincter.

Passing by these particulars, however, let us turn to others that bear

more immediately upon our subject. The uterine outlet or vulva, then, or

the passage from the common cavity to the uterus of the fowl, is a

certain protuberance, soft, lax, wrinkled, and orbicular, resembling the

orifice of the prepuce when closed, or appearing as if formed by a

prolapse of the internal membrane of the uterus. Now this outlet is

situated, as I have said, between the anus and rump, and slightly to the

left of the middle line of the body, which Ulysses Aldrovandi imagines

to be for the purpose of “facilitating intercourse, and the entrance of

the genital organ of the cock.” I have myself observed, however,

repeatedly, that the hen turned the common orifice to the right or left

indifferently, according to the side from which the cock approached her.

Neither do I find any penis in the cock--neither, indeed, could

Fabricius,--although in the goose and duck it is very conspicuous. But

in its stead I discover an orifice in the cock, not otherwise than in

the hen, although it is smaller and more contracted in her than in him;

and in the swan, goose, and duck the same thing also appears, the penis

of the male goose and duck protruding through this orifice during

intercourse.

In a black drake I noticed the penis of such a length that after

intercourse it trailed on the ground, and a fowl following, pecked at it

greedily, thinking it an earth-worm, as I imagine, so that it was

retracted more quickly than usual.

In the male ostrich I have found within this pudendal orifice a very

large glans, and the red body of the penis, as we discover them within

the prepuce of the horse, resembling a deer’s or a small neat’s tongue

in form and magnitude; and I have frequently observed this organ, rigid

and somewhat hooked during the coitus, and when entered into the vulva

of the female, held for some considerable time there without any

movement: it was precisely as if the two creatures had been fastened

together with a nail. Meantime, by the gesticulations of their heads and

necks, and by their noises, they seemed to notify their nuptials, and to

express the great degree of pleasure they experienced.

I have read in a treatise of Dr. Du Val, a learned physician of Rouen,

that a certain hermaphrodite was referred to the surgeons and

accoucheurs, that they might determine whether it were a man or a woman.

They, from an examination of the genital organs, adjudged the party to

be of the feminine gender, and a dress in accordance with this decision

was ordered. By and by, however, the individual was accused of

soliciting women, and of discharging the man’s office; and then it was

found, that from a prepuce, as from the private parts of a woman, a

penis protruded, and served to perform the male’s business. I have

myself occasionally seen the penis of a certain man so greatly shrunk in

size, that, unless when excited, nothing was visible in the wrinkled

prepuce above the scrotum but the extremity of the glans.

In the horse and some other animals, the principal and ample length of

the member is protruded from its concealment. In the mole, too, which is

a small animal, there is a remarkable retraction of the penis between

the skin and muscles of the belly; and the vulva in the female of this

creature is also longer and deeper than usual.

The cock, which is without a penis, performs copulation, as I imagine,

in the same manner as the smaller birds, among which the process is

rapidly executed, and by mere contact. The orifices of the male and

female cloaca, which at the moment are protuberant externally, which,

especially in the male, become tense and injected, like the glans penis,

encounter, and coition is effected by a succession of salutes, not by

any longer intromission of parts, for I do not think that the organs of

the cock enter those of the hen at all.

In the copulation of horses, dogs, cats, and the like, the female

presents her organ rigid and injected to the penis of the male. And this

also takes place in birds which, if they be tame and suffer themselves

to be handled, when inflamed with desire present their parts, which will

then be found resisting and hard to the finger.

Birds are sometimes so lustful, that if you but stroke their backs

gently with your hand, they will immediately lie down and expose and

protrude their uterine orifice; and if this part be touched with the

finger, they will not fail to proclaim their satisfaction. And that the

females may thereby be made to lay eggs, as testified to by

Aristotle,[135] I have myself found in the case of the blackbird,

thrush, and others. I learned the fact, indeed, in former years by

accident, and to my detriment; for my wife had a beautiful parrot, a

great pet, learned and talkative enough, and so tame that it was allowed

to roam at liberty about the house: when its mistress was absent it

sought her everywhere; on her return it caressed her, and loudly

proclaimed its joy; when called to it would answer; would fly to its

mistress, and then seizing her clothes with beak and feet alternately,

it climbed to her shoulder, whence creeping down the arm, it reached her

hand, its usual seat. When ordered to speak or to sing, it would obey,

although it were the night season and quite dark. Full of play and

lasciviousness, it would frequently sit in its mistress’s lap, where it

loved to have her scratch its head and stroke its back, upon which,

fluttering with its wings and making a gentle noise, it testified the

pleasure it experienced. I believed all this to proceed from his usual

familiarity and love of being noticed; for I always regarded the

creature as a male, by reason of his proficiency in talking and singing.

For among birds, the females rarely sing or challenge one another by

their note; the males alone solace their mates by their tuneful

warblings, and call them to the rites of love. And it is on this account

that Aristotle says,[136] “If partridges be placed over against the

males, and the wind blow towards them from where the males sit, they are

impregnated and conceive. They even for the most part conceive from the

note of the male bird, if they be in season and full of desire. The

flight of the male over them will also have the same effect, the male

bird casting down a fertilizing influence upon the female.” Now this

happens especially in the spring season, whence the poet sings:[137]

Earth teems in Spring, and craves the genial seed.

The almighty father, Æther, then descends,

In fertilizing showers, into the lap

Of his rejoicing spouse, and mingling there

In wide embrace sustains the progeny

Innumerous that springs. The pathless woods

Then ring with the wild bird’s song, and flocks and herds

Disport and spend the livelong day in love.

Not long after the caressings mentioned, the parrot, which had lived in

health for many years, fell sick, and by and by being seized with

repeated attacks of convulsions, seated in the lap of its mistress, it

expired, grievously regretted. Having opened the body in search of the

cause of death, I discovered an egg, nearly perfect, in the uterus, but

in consequence of the want of a male, in a state of putrefaction; and

this, indeed, frequently happens among birds confined in cages, which

show desire for the company of the male.

These and other instances induce me to believe that the common fowl and

the pheasant do not only solace their females with their crowing, but

farther give them the faculty of producing eggs by its means; for when

the cock crows in the night some of the hens perched near him bestir

themselves, clapping their wings and shaking their heads; shuddering and

gesticulating as they are wont to do after intercourse.

A certain bird, as large again as a swan, and which the Dutch call a

cassowary, was imported no long time ago from the island of Java, in the

East Indies, into Holland. Ulysses Aldrovandus[138] gives a figure of

this bird, and informs us that it is called an emeu by the Indians. It

is not a two-toed bird, like the ostrich, but has three toes on each

foot, one of which is furnished with a spur of such length, strength,

and hardness, that the creature can easily kick through a board two

fingers’ breadth in thickness. The cassowary defends itself by kicking

forwards. In the body, legs, and thighs it resembles the ostrich; it has

not a broad bill like the ostrich however, but one that is rounded and

black. On its head, by way of crest, it has an orbicular protuberant

horn. It has no tongue, and devours everything that is presented to

it--stones, coals, even though alight, pieces of glass--all without

distinction. Its feathers sprout in pairs from each particular quill,

and are of a black colour, short and slender, approaching to hair or

down in their characters. Its wings are very short and imperfect. The

whole aspect of the creature is truculent, and it has numbers of red and

blue wattles longitudinally disposed along the neck.

This bird remained for more than seven years in Holland, and was then

sent, among other presents, by the illustrious Maurice Prince of Orange,

to his serene majesty our King James, in whose gardens it continued to

live for a period of upwards of five years. By and by, however, when a

pair of ostriches, male and female, were brought to the same place, and

the cassowary heard and saw these in a neighbouring inclosure, at their

amours, unexpectedly it began to lay eggs, excited, as I imagine,

through sympathy with the acts of an allied genus; I say unexpectedly,

for all who saw the cassowary, judging from the weapons and ornaments,

had regarded it as a male rather than a female. Of these eggs, one was

laid entire, and this I opened, and found it perfect: the yelk

surrounded by the white, the chalazæ attached on either side, and a

small cavity in the blunt end; there was also a cicatricula or macula

alba present; the shell was thick, hard, and strong; and having taken

off the top, I had it formed into a cup, in the same way as ostrichs’

eggs are commonly fashioned. This egg was somewhat less than that of an

ostrich, and, as I have said, perfect in all respects. Undoubtedly,

however, it was a sort of accidental egg, and, by reason of the absence

of the male, unfruitful. I predicated the death of the cassowary as

likely to happen soon when she began laying, moved to do so by what

Aristotle says:[139] “Birds become diseased and die unless they produce

fruitful eggs.” And my prediction came true not long afterwards. On

opening the body of the cassowary, I discovered an imperfect and putrid

egg in the upper part of the uterus, as the cause of its untimely death,

just as I had found the same thing in the parrot, and other instances

besides.

Many birds, consequently, the more salacious they are, the more fruitful

are they; and occasionally, when abundantly fed, or from some other

cause, they will even lay eggs without the access of the male. It rarely

happens, however, that the eggs so produced are either perfected or

laid; the birds are commonly soon seized with serious disorders, and at

length die. The common fowl nevertheless not only conceives eggs, but

lays them, quite perfect in appearance too; but they are always wind

eggs, and incapable of producing a chick. In like manner many insects,

among the number silkworms and butterflies, conceive eggs and lay them,

without the access of the male, but they are still adventitious and

barren. Fishes also do the same.

It is of the same significance in these animals when they conceive eggs,

as it is in young women when their uterus grows hot, their menses flow,

and their bosoms swell--in a word, when they become marriageable; and

who, if they continue too long unwedded, are seized with serious

symptoms--hysterics, furor uterinus, &c. or fall into a cachectic state,

and distemperatures of various kinds. All animals, indeed, grow savage

when in heat, and unless they are suffered to enjoy one another, become

changed in disposition. In like manner women occasionally become insane

through ungratified desire, and to such a height does the malady reach

in some, that they are believed to be poisoned, or moon-struck, or

possessed by a devil. And this would certainly occur more frequently

than it does, without the influence of good nurture, respect for

character, and the modesty that is innate in the sex, which all tend to

tranquillize the inordinate passions of the mind.

EXERCISE THE SIXTH.

_Of the uterus of the fowl._

The passage from the external uterine orifice to the internal parts and

uterus itself, where the egg is perfected, is by that part which in

other animals is called the vagina or vulva. In the fowl, however, this

passage is so intricate, and its internal membrane is so loose and

wrinkled, that although there is a ready passage from within outwards,

and a large egg makes its way through all without much difficulty, still

it scarcely seems likely that the penis of the male could penetrate or

the spermatic fluid make its way through it; for I have found it

impossible to introduce either a probe or a bristle; neither could

Fabricius pass anything of the sort, and he says that he could not even

inflate the uterus with air. Whence he was led I fancy to give an

account of the uterus, proceeding from more internal to more external

parts. Considering this structure of the uterus also, he denies that the

spermatic fluid of the male can reach the cavity of the uterus, or go to

constitute any part of the egg.[140] To this statement I most willingly

subscribe; for, indeed, there is nothing in the fruitful egg which is

not also in the barren one; there is nothing in the way of addition or

change which indicates that the seminal fluid of the male has either

made its way into the uterus, or come into contact with the egg.

Moreover, although without the access of the cock all eggs laid are

winded and barren, still through his influence, and long after

intercourse, fruitful eggs are deposited, the rudiments or matter of

which did not exist at the time of the communication.

With a view to explaining how the spermatic fluid of the cock renders

eggs fecund, Fabricius says:[141] “Since the semen does not appear in

the egg, and yet is thrown into the uterus by the cock, it may be asked

why this is done if the fluid does not enter the egg? Farther: if not

present in the egg, how is that egg made fruitful by the spermatic fluid

of the cock which it yet does not contain? My opinion is that the semen

of the cock thrown into the commencement of the uterus, produces an

influence on the whole of the uterus, and at the same time renders

fruitful the whole of the yelks, and finally of the perfect eggs which

fall into it; and this the semen effects by its peculiar property or

irradiative spirituous substance, in the same manner as we see other

animals rendered fruitful by the testicles and semen. For if any one

will but bring to mind the incredible change that is produced by

castration, when the heat, strength, and fecundity are lost, he will

readily admit that what we have proposed may happen in reference to the

single uterus of a fowl. But that it is in all respects true, and that

the faculty of impregnating the whole of the ova, and also the uterus

itself, proceeds from the semen of the cock, appears from the custom of

those housewives who keep hens at home but no cock, that they commit

their hens for a day or two to a neighbour’s cock, and in this short

space of time the whole of the eggs that will be laid for a certain

season are rendered prolific. And this fact is confirmed by

Aristotle,[142] who will have it that, among birds, one intercourse

suffices to render almost all the eggs fruitful. For the fecundating

influence of the seminal fluid, as it cannot exhale, so is it long

retained in the uterus, to which it imparts the whole of its virtue;

nature herself stores it up, placing it in a cavity appended to the

uterus, near the fundament, furnished with an entrance only, so that,

being there laid up, its virtue is the better preserved and communicated

to the entire uterus.”