But it is obvious that neither is the egg engendered by the cock and hen

in this way; for the hen in the act of intercourse emits no semen from

which an egg might be formed; nor can aught like a seminal fluid of the

hen be demonstrated at any time; and indeed the animal is destitute of

the organs essential to its preparation, the testes and vasa spermatica.

And though the hen have an effective force in common with the cock (as

must be manifest from what precedes), and it is a mixture of some sort

that renders an egg fruitful, still this does not happen according to

the predominance of the genitures, or the manner of their mixture, for

it is certain, and Fabricius admits it, that the semen of the cock does

not reach the cavity of the uterus; neither is there any trace of the

egg to be discovered in the uterus immediately after intercourse, and as

its consequence, although Aristotle himself repeatedly avers that there

is, asserting that “something of the conception forthwith ensues.” But I

shall by and by demonstrate that neither does any such imaginary mixture

of seminal fluids take place in any animal, nor that immediately upon

intercourse, even of a fruitful kind, is there anything in the shape of

semen or blood, or of the rudiments of an embryo present or demonstrable

in the cavity of the uterus. Nothing is found in the egg or embryo which

leads us to suppose that the semen masculinum is either there contained

or mingled. The vulgar notion of the chalazæ being the tread of the cock

is a sheer mistake; and I am surprised, since there are two of them, one

in either end of the egg, that no one has yet been found to maintain

that this was the cock’s seed, that the hen’s. But this popular error is

at once answered by the fact that the chalazæ are present with the same

characters in every egg, whether it be fertile or barren.

EXERCISE THE THIRTY-THIRD.

_The male and the female are alike efficient in the business of

generation._

The medical writers with propriety maintain, in opposition to the

Aristotelians, that both sexes have the power of acting as efficient

causes in the business of generation; inasmuch as the being engendered

is a mixture of the two which engender: both form and likeness of body,

and species are mixed, as we see in the hybrid between the partridge and

common fowl. And it does indeed seem consonant with reason to hold that

they are the efficient causes of conception whose mixture appears in the

thing produced.

Aristotle entertaining this opinion says:[225] “In some animals it is

manifest that such as the generator is, such is the engendered; not,

however, the same and identical, not one numerically, but one

specifically, as in natural things. A man engenders a man, if there be

nothing preternatural in the way, as a horse [upon an ass] engenders a

mule, and other similar instances. For the mule is common to the horse

and the ass; it is not spoken of as an allied kind; yet may horse and

ass both be there conjoined in a hybrid state.” He says farther in the

same place: “It is enough that the generator generate, and prove the

cause that the species be found in the matter: for such and such an

entire species is still found associated with such and such flesh and

bones--here it is Gallias, there it is Socrates.”

Wherefore if such an entire form, as a mule, be a mixture of two, viz.:

a horse and an ass, the horse does not suffice to produce this form of a

mule in the ‘matter;’ but, as the entire form is mixed, so another

efficient cause is contributed by the ass and added to that supplied by

the horse. That, therefore, which produces a mule compounded of two,

must itself be an ‘adequate efficient,’ and mixed, if only ‘univocal.’

For example, this woman and that man engender this Socrates; not in so

far as they are both human beings, and of one and the same species, but

in so far as this man and that woman in these bones and muscles

constitute human forms, of both of which, if Socrates be a certain

mixture, a compound of both, that by which he is made must needs be a

mixed univocal compound of the two; i. e. a mixed efficient of a mixed

effect. And therefore it is that the male and female by themselves, and

separately, are not genetic, but become so united _in coitu_, and made

one animal as it were; whence, from the two as one, is produced and

educed that which is the true efficient proximate cause of conception.

The medical writers also, in directing their attention to the

particulars of human generation alone, come to conclusions on generation

at large; and the spermatic fluid proceeding from the parents _in coitu_

has in all probability been taken by them for true seed, analogous to

the seeds of plants. It is not without reason, therefore, that they

imagine the mixed efficient cause of the future offspring to be

constituted by a mixture of the seminal matters of each parent. And then

they go on to assert that the mixture proceeding immediately from

intercourse is deposited in the uterus and forms the rudiments of the

conception. That things are very different, however, is made manifest by

our preceding history of the egg, which is a true conception.

EXERCISE THE THIRTY-FOURTH.

_Of the matter of the egg, in opposition to the Aristotelians and the

medical writers._

The position taken up by the medical writers against the Aristotelians,

viz., that the blood is not the first element in a conception, is

clearly shown from the generation of the egg to be well chosen: neither

during intercourse, nor before nor after it, is there a drop of blood

contained in the uterus of the fowl; neither are the rudiments of eggs

red, but white. Many animals also conceive in whose uteri, if they be

suddenly laid open after intercourse, no blood can be demonstrated.

But when they contend that the maternal blood is the food of the fœtus

in utero, especially of its more sanguineous parts, as they style them,

and that the fœtus from the outset is as it were a portion of the

mother, being nourished and growing through her blood, and vegetating

through her spirit; so that neither does the heart pulsate, nor the

liver compose blood, nor any part of the fœtus perform any kind of

independent office, but everything is carried on through the mother’s

means, they in their turn are as certainly mistaken, and argue from

erroneous observations. For the embryo in the egg boasts of its own

blood, formed from the fluids contained within the egg; and its heart is

seen to pulsate from the very beginning: it borrows nothing in the shape

either of blood or spirits from the hen, for the purpose of forming its

so called sanguineous parts and its feathers; as most clearly appears to

any one who looks on with an unbiassed mind. From observations

afterwards to be communicated, I believe indeed that it will be held as

sufficiently proven that even the fœtus of viviparous animals still

contained in the uterus is not nourished by the blood of the mother and

does not vegetate through her spirit; but boasts of its own peculiar

vital principle and powers, and its own blood, like the chick in ovo.

With reference to the matter which the embryo obtains from its male and

female parent, however, and the way and manner of generation as commonly

discoursed of in the schools, viz.: that conception is produced or

becomes prolific from mixture of the genitures and their mutual action

and passion, as also of the seminal fluid of the female, and the parts

which are spoken of as sanguineous and spermatic, numerous and striking

observations afterwards to be related have compelled me to adopt

opinions at variance with all such views. At this time I shall only say

that I am greatly surprised how physicians, particularly those among

them who are conversant with anatomy, should pretend to support their

opinions by means of two arguments especially, which rightly understood,

seem rather to prove the opposite; viz., from the shock and resolution

of the forces and the effusion of fluid which women at the moment of the

sexual orgasm frequently experience, they argue that all women pour out

a seminal fluid, and that this is necessary to generation.

But passing over the fact that the females of all the lower animals, and

all women, do not experience any such emission of fluid, and that

conception is nowise impossible in cases where it does not take place,

for I have known several, who without anything of the kind were

sufficiently prolific, and even some who after experiencing such an

emission and having had great enjoyment, nevertheless appeared to have

lost somewhat of their wonted fecundity; and then an infinite number of

instances might be quoted of women who, although they have great

satisfaction in intercourse, still emit nothing, and yet conceive;

passing over these facts, I say, I cannot but express surprise at those

especially, who, conceiving such an emission on the part of the female

necessary to conception, have not adverted to the fact that the fluid

emitted is discharged, cast out, and is particularly abundant about the

clitoris and orifice of the vulva; that it is seldom poured out within

the vulva, never within the uterus, and so as to be mingled with the

semen of the male; moreover, it is of a mere serous or ichorous

consistency, like urine, by no means thick and apparently unctuous, like

the spermatic matter of the male. But how shall we suppose that to be of

use internally which is discharged externally? Or shall we say that this

humour, as if bidding the uterus farewell, is taken to the verge of the

vulva, that it may be then recalled with greater favour by the uterus?

The other argument is drawn from the genital organs of women, the

testes, to wit, and vasa spermatica, præparantia et deferentia, which

are held to serve for the preparation of the spermatic fluid. I, for my

part, greatly wonder how any one can believe that from parts so

imperfect and obscure, a fluid like the semen, so elaborate, concoct and

vivifying, can ever be produced, endowed with force and spirit and

generative influence adequate to overcome that of the male; for this is

implied in the discussion concerning the predominance of the male or the

female, as to which of them is to become the agent and efficient cause,

which the matter and pathic principle. How should such a fluid get the

better of another concocted under the influence of a heat so fostering,

of vessels so elaborate, and endowed with such vital energy?--how should

such a fluid as the male semen be made to play the part of mere

matter?--But of these things more hereafter.

Meantime it is certain that the egg of the hen is not engendered from

any such discharge of fluid during sexual intercourse, although after

connexion, and brimful of satisfaction, she shakes herself for joy,

and, as if already possessed of the richest treasure, as if gifted by

supreme Jove the preserver with the blessing of fecundity, she sets to

work to prune and ornament herself. The pigeon, particularly that kind

which comes to us from Africa, expresses the satisfaction she feels from

intercourse in a remarkable manner; she leaps, spreads her tail, and

sweeps the ground with its extremity, she pecks and prunes her

feathers--all her actions are as if she felt raised to the summit of

felicity by the gift of fruitfulness.

We have said that the primary matter of the egg does not consist of

blood as Aristotle would have it, neither does it proceed from any

mixture of the male and female seminal fluids. Whence it truly

originates we have already stated in part in our history; and we shall

by and by have occasion to speak of the subject more at length when we

come to treat generally of the matter from which every conception is

originally produced.

EXERCISE THE THIRTY-FIFTH.

_In how far is the fowl efficient in the generation of the egg,

according to Aristotle? And wherefore is the concurrence of the male

required?_

It has been already stated that the cock and hen are the two principles

in the generation of the egg, although of the manner in which they are

so I am of a different opinion from Aristotle and medical authorities.

From the production of the egg we have clearly shown that the female as

well as the male was efficient, and that she had within her a principle

whence motion and the faculty of forming flowed; although in the sexual

act the male neither confers the matter, nor does the female eject any

semen whence the egg is constituted. It is consequently manifest, in

some animals at least, that nature has not, on account of the

distinction into male and female, established it as a law that the one,

as agent, should confer form, the other, as passive, supply matter, as

Aristotle apprehended; nor yet that during intercourse each should

contribute a seminal fluid, by the mixture of which a conception or

ovum should be produced, as physicians commonly suppose.

Now since everything that has been delivered by the ancients on

generation is comprehended in these two opinions, it appears to have

escaped every one up to this time, first, why the hen by herself does

not generate, like vegetables, but requires a male to be associated with

her in the work; and then how the conception or ovum is procreated by

the male and the female together, or what either of them contributes to

the process, and for what end intercourse was established.

Aristotle, in opposition to the entire tenor of his hypothesis, viz.

that the male is to be regarded as the agent, the female as supplying

the matter only, when he sees that eggs are actually produced by hens

without the concurrence of the male, is compelled to admit that the

female is likewise efficient; he was farther not ignorant of the fact

that an egg even when extruded could preserve itself, nourish itself,

increase in size and produce an embryo, as happens with the eggs of

fishes; and he has besides accorded a vital principle to an egg, even to

a hypenemic one. But he endeavours to explain to what extent a female is

efficient, and how a hypenemic egg is endowed with a vital principle, in

the passage where he says[226]: “Hypenemic eggs admit of generation to a

certain point; for that they can ever go the length of producing an

animal is impossible, this being the work of the senses [the sensible

soul]. But females and all things that live, as already repeatedly

stated, possess the vegetative soul. Wherefore the hypenemic egg as a

vegetable is perfect, but as an animal it is imperfect.” By this he

seems to insinuate that the hypenemic egg is possessed of a vegetative

soul, inasmuch as this is inherent in all things that live, and an egg

is alive. In like manner he ascribes to the hen the power of creating

and of conferring the vegetative soul; because all females acquire this

virtue, so that a hypenemic egg in so far as it lives as a vegetable is

perfect, in so far as it is an animal however it is imperfect. As if a

male were not required that a conception or ovum should be produced, and

produced perfect; but that from this ovum an animal should be

engendered. Not, I say, that an egg be produced as perfect in all

respects as is the conception of a vegetable; but that it should be

imbued with the animal principle. The egg, consequently, is formed by

the hen, but it is made prolific by the cock.

Aristotle adds in the same place: “There is a distinction of sexes

through the whole class of birds. And therefore it happens that the hen

perfects her egg, not yet influenced by the intercourse of the male, in

so far as it is a plant; but as it is not a plant, there she does not

perfect it: nor does anything come of it which engenders. For neither

has it arisen simply, like the seed of a plant, nor like an animal

conception, by intercourse.” He is here speaking of the wind egg; by and

by he adds: “But those eggs that are conceived through intercourse are

already characterized in a portion of the albumen: such eggs become

fruitful through the male which first copulated, for they are then

supplied with both principles.”

By this he seems to confess that the female is also effective in the

work of generation, or is possessed of the faculty of engendering;

because in every female there inheres a vegetative soul, whose faculty

it is to engender. And, therefore, when he is speaking of the

differences between the male and female, he still acknowledges both as

generative; for he says: “We call that animal male which engenders in

another, female that which engenders in itself.” From his own showing,

therefore, both engender; and as there is a vegetative soul inherent in

both, so is there also its faculty of generation. But how they differ

has already been shown in the History of the Egg: the hen generates of

herself without the concurrence of the cock, as a plant out of itself

produces fruit; but it is a wind egg that is thus produced: it is not

made fruitful without the concurrence of the cock either preceding or

succeeding. The female generates, then, but it is only up to a certain

mark, and the concurrence of the male is requisite that this faculty of

engendering be made complete, that she may not only lay an egg, but such

an egg as will, under favorable circumstances, produce a pullet. The

male appears to be ordained by nature to supply this deficiency in the

generative powers of the female, as will be clearly shown by and by, and

that that which the female of herself cannot accomplish, viz. the

production of a fruitful egg, may be supplied and made good by the act

of the male, who imparts this virtue to the fowl or the egg.

EXERCISE THE THIRTY-SIXTH.

_The perfect hen’s egg is of two colours._

Every egg, then, is not perfect; but some are to be held imperfect

because they have not yet attained their true dimensions, which they

only receive when extruded; others are imperfect because they are yet

unprolific, and only acquire a fertilizing faculty from without, such

are the eggs of fishes. Other eggs again are held imperfect by

Aristotle, because they are of one colour only, inasmuch as perfect eggs

consist of yelk and albumen, and are of two colours, as if better

concocted, more distinct in their parts, endowed with higher heat. The

eggs that are called centenine or hundredth eggs, and which

Fabricius[227] will have it are engendered of certain remainders of

albumen, are of one colour only, and by reason of their deficiency of

heat and their weakness, are regarded as imperfect. Of all eggs, there

are none more perfect than those of the hen, which are produced complete

in all their fluids and appendages, of proper size and fruitful.

Aristotle assigns the following reason wherefore some eggs are of two

colours, others of one hue only:[228] “In the hotter animals those

things from which the principles of their origin are derived, are

distinct and separate from those which furnish their nutrition; now the

one of these is white, the other is yellow.” As if the chick derived its

origin from the albumen and was nourished by the vitellus alone. In the

same place he proceeds thus: “That part which is hot contributes

properly to the form in the constitution of the extremities; but the

part that is more earthy, and is further removed, supplies material for

the trunk. Whence in eggs of two colours the animal derives its origin

from the white, for the commencement of animal existence is in the

white; but the nourishment is obtained from the yellow.” He consequently

thinks that this is the reason why these fluids are distinct, and why

eggs are produced of two colours.

Now these ideas are partly true, partly false. It is not true, for

instance, that the embryo of the common fowl is first formed from the

albumen and then nourished by the vitellus; for, from the history of the

formation of the chick in ovo, from the course of the umbilical vessels

and the distribution of their branches, which undoubtedly serve for

obtaining nourishment, it obviously appears that the constituent matter,

and the nutriment are supplied to the chick from its first formation by

the yelk, as well as the white; the fluid which we have called the

colliquament seems farther to be supplied, not less by the vitellus than

the albumen; a certain portion of both the fluids seems, in fact, to be

resolved. And then the spot, by the expansion of which the colliquament

is formed in the first instance, and which we have called the eye,

appears to be impressed upon the membrane of the vitellus.

The distinction into yellow and white, however, seems to be a thing

necessary: these matters, as they are undoubtedly of different natures,

appear also to serve different offices; they are therefore completely

separate in the perfect egg, one of them being more the other less

immediately akin to proper alimentary matter; by the one the fœtus is

nourished from the very beginning, by the other it is nourished at a

later period. For it is certain, as Fabricius asserts, and as we

afterwards maintain, that both of them are truly nutritious, the albumen

as well as the vitellus, the albumen being the first that is consumed. I

therefore agree with Aristotle against the physicians, that the albumen

is the purer portion of the egg, the better concocted, the more highly

elaborated; and, therefore, whilst the egg is getting perfected in the

uterus, is the albumen as the hotter portion poured around in the

circumference, the yelk or more earthy portion subsiding to the centre.

For the albumen appears to contain the larger quantity of animal heat,

and so to be nutriment of a more immediate kind. For like reasons it is

probable that the albumen is purer and better concocted externally than

it is internally.

When medical writers affirm that the yelk is the hotter and more

nutritious portion of the egg, this I imagine is meant as it affords

food to us, not as it is found to supply the wants of the chick in ovo.

This, indeed, is obvious from the history of the formation of the chick,

by which the thin albumen is absorbed and used up sooner than the

thick, as if it formed the more appropriate aliment, and were more

readily transmuted into the substance of the embryo, of the chick that

is to be. The yelk, therefore, appears to be a more distant or ultimate

aliment than the albumen, the whole of which has been used up before any

notable portion of the vitellus is consumed. The yelk, indeed, is still

found inclosed within the abdomen of the chick after its exclusion from

the shell, as if it were destined to serve the new being in lieu of milk

for its sustenance.

Eggs, consisting of white and yellow, are therefore more perfect, as

more distinct in constitution, and elaborated by a higher temperature.

For in the egg there must be included, not only the matter of the chick

but also its first nutriment; and what is provided for a perfect animal,

must, itself, be perfect and highly elaborated; as that is, in fact,

which consists of different parts, some of which, as already stated, are

prior and purer, and so more easy of digestion; others posterior, and

therefore more difficult of transmutation into the substance of the

chick. Now the yelk and albumen differ from one another by such kinds of

distinction. Perfect eggs are, consequently, of two colours: they

consist of albumen and yelk, as if these constituted fluids of easier or

more difficult digestion, adapted to the different ages and vigour of

the chick.

EXERCISE THE THIRTY-SEVENTH.

_Of the manner in which the egg is increased by the albumen._

From the history it appears that the rudiments of the eggs in the ovary

are of very small size, mere specks, smaller than millet seeds, white

and replete with watery fluid: these specks, however, by and by, become

yelks, and then surround themselves with albumen.

Aristotle seems to think that the albumen is generated in the way of

secretion from the vitellus. It may be well to add his words:[229] “The

sex,” he says, “is not the cause of the double colour, as if the white

were derived from the male, the yellow from the female; both are

furnished by the female. But one of them is hot, the other is cold. Now

these two portions are distinct in animals, fraught with much heat; in

those that are not so fraught the eggs are not thus distinct. And this

is the reason why the conceptions of these are of one colour. But the

semen of the male alone sets the conception; therefore is the conception

of the bird small and white in the first instance; but in the course of

time, and when there is a larger infusion of blood, it becomes entirely

yellow; and, last of all, when the heat declines, the white portion, as

a humour of equal temperature surrounds it on every side. For the white

portion of the egg is, by its nature, moist, and includes animal heat in

itself; and it is for this reason that it is seen in the circumference,

the yellow and earthy portion remaining in the interior.”

Fabricius,[230] however, thinks that “the albumen only adheres to the

vitellus by juxtaposition. For while the yelk is rolled through the

second uterus and gradually descends, it also gradually assumes to

itself the albumen which is there produced, and made ready, that it may

be applied to the yelk; until the yelk having passed the middle spirals

and reached the last of them, already surrounded with the albumen, it

now surrounds itself with the membranes and shell.” Fabricius will

therefore have it that the egg increases in a two-fold manner: “partly

by means of the veins, as concerns the vitellus, and partly by an

appositive increase, as regards the albumen.” And, among other reasons,

this was perchance one for the above opinion: that when an egg is boiled

hard the albumen is readily split into layers lying one over another.

But this also occurs to the yelk still connected with the ovary, when

boiled hard.

Wherefore, taught by experience, I rather incline to the opinion of

Aristotle; for the albumen is not merely perceived as added in the way

Fabricius will have it, but fashioned also, distinguished by chalazæ and

membranes, and divided into two different portions; and all this in

virtue of the inherence of the same vegetative vital principle by which

the egg is more conspicuously divided into two distinct substances--a

yelk and a white. For the same faculty that presides over the formation

of the egg in general, presides over the constitution of each of its

parts in particular. Neither is it altogether true that the yelk is

first formed and the albumen added to it afterwards; for what is seen in

the ovary is not the vitellus of the egg, but rather a compound

containing the two liquids mingled together. It has the colour of the

vitellus, indeed, but in point of consistence it is more like the

albumen; and when boiled hard it is not friable like the proper yelk,

but, like the white, is concreted, jelly-like, and seen to be composed

of thin lamellæ; and it has a kind of white papula, or spot, in the

middle.

Aristotle seems to derive this separation from the dissimilar nature of

the yelk and white; for he says,[231] as we have already stated, that if

a number of eggs be thrown into a pan and boiled, in such wise that the

heat shall not be quicker than the separation of the eggs, (citatior

quam ovorum distinctio,) the same thing will take place in the mass of

eggs which occurs in the individual egg: the whole of the yelks will set

in the middle, the whites round about them.

This I have myself frequently found to be true on making the trial, and

it is open to any one to repeat the experiment; let him only beat yelks

and whites together, put the mixture into a dutch oven, or between two

plates over the fire, and having added some butter, cause it to set

slowly into a cake, he will find the albumen covering over the yelks

situated at the bottom.

EXERCISE THE THIRTY-EIGHTH.

_Of what the cock and hen severally contribute to the production of the

egg._

Both cock and hen are to be reputed parents of the chick; for both are

necessary principles of an egg, and we have proved both to be alike its

efficient: the hen fashions the egg, the cock makes it fertile. Both,

consequently, are instruments of the plastic virtue by which this

species of animal is perpetuated.

But as in some species there appears to be no occasion for males,

females sufficing of themselves to continue the kind; so do we discover

no males among these, but females only, containing the fertile rudiments

of eggs in their interior; in other species, again, none but males are

discovered which procreate and preserve their kinds by emitting

something into the mud, or earth, or water. In such instances nature

appears to have been content with a single sex, which she has used as an

instrument adequate to procreation.

Another class of animals has a generative fluid fortuitously, as it

were, and without any distinction of sex; the origin of such animals is

spontaneous. But “as some things are made by art, and some depend on

accident, health for example,”[232] so also some semen of animals is not

produced by the act of an individual agent, as in the case of a man

engendered by a man; but in some sort univocally, as in those instances

where the rudiments and matter, produced by accident, are susceptible of

taking on the same motions as seminal matter, as in “animals which do

not proceed from coitus, but arise spontaneously, and have such an

origin as insects which engender worms.”[233] For as mechanics perform

some operations with their unaided hands, and others not without the

assistance of particular tools; and as the more excellent and varied and

curious works of art require a greater variety in the form and size of

the tools to bring them to perfection, inasmuch as a greater number of

motions and a larger amount of subordinate means are required to bring

more worthy labours to a successful issue--art imitating nature here as

everywhere else, so also does nature make use of a larger number and

variety of forces and instruments as necessary to the procreation of the

more perfect animals. For the sun, or Heaven, or whatever name is used

to designate that which is understood as the common generator or parent

of all animated things, engenders some of themselves, by accident,

without an instrument, as it were, and equivocally; and others through

the concurrence of a single individual, as in those instances where an

animal is produced from another animal of the same genus which supplies

both matter and form to the being engendered; so in like manner in the

generation of the most perfect animals where principles are

distinguished, and the seminal elements of animated beings are divided,

a new creation is not effected save by the concurrence of male and

female, or by two necessary instruments. Our hen’s egg is of this kind;

to its production in the perfect state the cock and the hen are

necessary. The hen engenders in herself, and therefore does she supply

place and matter, nutriment and warmth; but the cock confers fecundity;

for the male, as Aristotle says,[234] always perfects generation,

secures the presence of a sensitive vital principle, and from such an

egg an animal is engendered.

To the cock, therefore, as well as to the hen, are given the organs

requisite to the function with which he is intrusted; in the hen all the

genital parts are adapted to receive and contain, as in the cock they

are calculated to give and immit, or prepare that which transfers

fecundity to the female, he engendering, as it were, in another, not in

himself.

When we anatomize the organs appropriated to generation, therefore, we

readily distinguish what each sex contributes in the process; for a

knowledge of the instruments here leads us by a direct path to a

knowledge of their functions.

EXERCISE THE THIRTY-NINTH.

_Of the cock and the particulars most remarkable in his constitution._

The cock, as stated, is the prime efficient of the perfect or fruitful

hen’s egg, and the chief cause of generation: without the male no chick

would ever be produced from an egg, and in many ovipara not even would

any egg be produced. It is, therefore, imperative on us that we look

narrowly into his offices and uses, and inquire particularly what he

contributes to the egg and chick, both in the act of intercourse and at

other times.

It is certain that the cock in coition emits his ‘geniture,’ commonly

called semen, from his sexual parts, although he has no penis, as I

maintain; because his testes and long and ample vasa deferentia are full

of this fluid. But whether it issues in jets, with a kind of spirituous

briskness and repeatedly as in the hotter viviparous animals, or not, I

have not been able to ascertain. But as I do not find any vesiculæ

containing semen, from which, made brisk and raised into a froth by the

spirits, it might be emitted; nor any penis through whose narrower

orifice it might be forcibly ejaculated, and so strike upon the interior

of the hen; and particularly when I see the act of intercourse so

rapidly performed between them; I am disposed to believe that the parts

of the hen are merely moistened with a very small quantity of seminal

fluid, only as much as will adhere to the orifice of the pudenda, and

that the prolific fluid is not emitted by any sudden ejaculation; so

that whilst among animals repeated ejaculations take place during the

same connection, among birds, which are not delayed with any complexity

of venereal apparatus, the same object is effected by repeated

connections. Animals that are long in connection, copulate rarely; and

this is the case with the swan and ostrich among birds. The cock,

therefore, as he cannot stay long in his connections, supplies by dint

of repeated treadings the reiterated ejaculations of the single

intercourse in other animals; and as he has neither penis nor glans,

still the extremities of the vasa deferentia, inflated with spirits when

he treads, become turgid in the manner of a glans penis, and the orifice

of the uterus of the hen, compressed by them, her cloaca being exposed

for the occasion, is anointed with genital fluid, which consequently

does not require a penis for its intromission.

We have said, however, that such was the virtue of the semen of the

cock, that not only did it render the uterus, the egg in utero, and the

vitelline germ in the ovary, but the whole hen prolific, so that even

the germs of vitelli, yet to be produced, were impregnated.

Fabricius has well observed, that the quantity of spermatic fluid

contained in the testes and vasa deferentia of the cock was large; not

that the hen requires much to fecundate each of her eggs, but that the

cock may have a supply for the large number of hens he serves and for

his repeated addresses to them.

The shortness and straight course of the spermatic vessels in the cock

also assist the rapid emission of the spermatic fluid: anything that

must pass through lengthened and tortuous conduits of course escapes

more slowly and requires a greater exercise of the impelling power or

spirit to force it away.

Among male animals there is none that is more active or more haughty and

erect, or that has stronger powers of digestion than the cock, which

turns the larger portion of his food into semen; hence it is that he

requires so many wives,--ten or even a dozen. For there are some

animals, single males of which suffice for several females, as we see

among deer, cattle, &c.; and there are others, of which the females are

so prurient that they are scarcely satisfied with several males, such as

the bitch and the wolf; whence prostitutes were called _lupæ_ or wolves,

as making their persons common; and stews were entitled _lupanaria_.

Whilst some animals, of a more chaste disposition, live, as it were, in

the conjugal estate, so that the male is married to a single female

only, and both take part in providing for the wants of the family; for

since nature requires that the male supply the deficiencies of the

female in the work of generation, and as she alone in many cases does

not suffice to cherish and feed and protect the young, the male is added

to the wife that he may take part in the burthen of bringing up the

offspring. Partridges lead a wedded life, because the females alone

cannot incubate such a number of eggs as they lay, (so that they are

said, by some, to make two nests,) nor to bring up such a family as by

and by appears without assistance. The male pigeon also assists in

building the nest, takes his turn in incubating the eggs, and is active

in feeding the young. In the same way many other instances of conjugal

life among the lower animals might be quoted, and indeed we shall have

occasion to refer to several in what yet remains to be said.

Those males, among animals, which serve several females, such as the

cock, have an abundant secretion of seminal fluid, and are provided with

long and ample vasa deferentia. And at whatever time or season the

clustered rudimentary papulæ in the ovary come to maturity and require

fecundation, that they may go on to be turned into perfect eggs, the

males will then be found to have an abundance of seminal fluid, and the

testicles to enlarge and become conspicuous in the very situation to

which they transfer their fecundating influence, viz. the præcordia.

This is remarkable in fishes, birds, and the whole race of oviparous

animals; the males of which teem with fecundating seminal fluid at the

same precise seasons as the females become full of eggs.

Whatever parts of the hen, therefore, are destined by nature for

purposes of generation, viz. the ovary, the infundibulum, the processus

uteri, the uterus itself, and the pudenda; as also the situation of

these parts, their structure, dimensions, temperature, and all that

follows this; all these, I say, are either subordinate to the production

and growth of the egg, or to intercourse and the reception of fecundity

from the male; or, for the sake of parturition, to which they conduce

either as principal and convenient means, or as means necessary, and

without which what is done could not be accomplished; for nothing in

nature’s works is fashioned either carelessly or in vain. In the same

way all the parts in the cock are fashioned subordinate to the

preparation or concoction of the spermatic fluid, and its transference

to the hen.

Now those males that are so vigorously constituted as to serve several

females are larger and handsomer, and in the matter of spirit and arms

excel their females in a far greater degree than the males of those that

live attached to a single female. Neither the male partridge, nor the

crow, nor the pigeon, is distinguished from the female bird in the same

decided way as the cock from his hens, the stag from his does, &c.

The cock, therefore, as he is gayer in his plumage, better armed, more

courageous and pugnacious, so is he replete with semen, and so apt for

repeated intercourse, that unless he have a number of wives he

distresses them by his frequent assaults; he not only invites but

compels them to his pleasure, and leaping upon them at inconvenient and

improper seasons, (even when they are engaged in the business of

incubation) and wearing off the feathers from their backs, he truly does

them an injury. I have occasionally seen hens so torn and worn by the

ferocious addresses of the cock, that with their backs stript of

feathers and laid bare in places, even to the bone, they languished

miserably for a time and then died. The same thing also occurs among

pheasants, turkeys, and other species.

EXERCISE THE FORTIETH.

_Of the hen._

There are two instruments and two first causes of generation, the male

and the female--for to the hen seems to belong the formation of the egg,

as to the cock the fertilizing principle. In the act of intercourse,

then, of these two, that which renders the egg fruitful is either

transmitted from the male to the female, or by means of coition is

generated in the hen. The nature of this principle, however, is no less

difficult to ascertain than are the particulars of its communication,

whether, for instance, we suppose such communication to take place with

the whole system of the hen, or simply with her womb, or with the egg

already formed, or further, with all the eggs now commencing and

hereafter about to commence their existence in the ovary. For it is

probable, from what I have formerly mentioned, and also from the

experiment of Fabricius,[235] that but a few acts of intercourse, and

the consorting of the hen with the cock for some days, are sufficient to

fecundate her, or at least her womb, during the whole year. And so far I

can myself affirm, from my own observation, to wit, that the twentieth

egg laid by a hen, after separation from the cock, has proved prolific.

So that, in like manner as it is well known that, from the seed of male

fishes shed into the water, a large mass of ova is impregnated, and that

in dogs, pigs, and other animals, a small number of acts of intercourse

suffice for the procreation of many young ones, (some even think it well

established, that if a bitch have connexion more than three or four

times, her fruitfulness is impaired, and that more females than males

are then engendered), so may the cock, by a few treadings, render

prolific not only the egg in the womb, but also the whole ovarium, and,

as has been often said, the hen herself. Nay, what is more remarkable,

and indeed wonderful, it is said that in Persia,[236] on cutting open

the female mouse, the young ones still contained in the belly are

already pregnant; in other words, they are mothers before they are

born! as if the male rendered not only the female fruitful, but also

impregnated the young which she had conceived; in the same way as our

cock fertilizes not merely the hen, but also the eggs which are about to

be produced by her.

But this is confidently denied by those physicians who assert that

conception is produced from a mixture of the seed of each sex. And hence

Fabricius,[237] although he affirms that the seed of the cock ejected in

coition never does, nor can, enter the cavity of the womb, where the egg

is formed, or takes its increase, and though he plainly sees that the

eggs when first commencing in the ovarium are, no less than those which

exist in the womb, fecundated by the same act of coition, and that of

these no part could arise from the semen of the cock, yet has he

supposed that this semen, as if it must needs be present and permanent,

is contained during the entire year in the “bursa” of the fruitful hen,

and reserved in a “foramen cæcum.” This opinion we have already

rejected, as well because that cavity is found in the male and female

equally, as because neither there, nor anywhere else in the hen, have we

been able to discover this stagnant semen of the cock; as soon as it has

performed its office, and impressed a prolific power on the female, it

either escapes out of the body, or is dissolved, or is turned into

vapour and vanishes. And although Galen,[238] and all physicians with

him, oppose by various reasonings this dissolving of the semen, yet, if

they carefully trace the anatomical arrangement of the genital parts,

and at the same time weigh other proofs of the strongest kind, they must

confess that the semen of the male, as it is derived from the testicles

through the vasa deferentia, and as it is contained in the vesiculæ

seminales, is not prolific unless it be rendered spiritual and

effervesce into a frothy nature by the incitement of intercourse or

desire. For it is not, as Aristotle[239] bears witness, its bodily form,

or fire, or any such faculty, that renders the semen prolific, but the

spirit which is contained in it, and the nature which inheres in it,

bearing a proportion to the element of the stars. Wherefore, though we

should allow with Fabricius that the semen is retained in the “bursa,”

yet, when that prolific effervescence or spirit had been spent, it

would forthwith be useless and sterile. Hence, too, physicians may learn

that the semen of the male is the architect of the progeny, not because

the first conception is embodied out of it, but because it is spiritual

and effervescent, as if swelling with a fertilising spirit, and a

preternatural influence. For otherwise the story of Averrhöes, of the

woman who conceived in a bath, might bear an appearance of truth. But of

these things more in their proper place.

In the same manner then as the egg is formed from the hen, so is it

probable, that from the _females_ of other animals, as will hereafter be

shown, the first conceptions take both material and form; and that, too,

some little time after the semen of the male has been introduced, and

has disappeared again. For the cock does not confer any fecundity on the

hen, or her eggs, by the simple emission of his semen, but only in so

far as that fluid has a prolific quality, and is imbued with a plastic

power; that is to say, is spiritual, operative, and analogous to the

essence of the stars. The male, therefore, is no more to be considered

the first principle, from which conceptions and the embryo arise,

because he is capable of secreting and emitting semen, than is the

female, which creates an egg without his assistance. But it is on this

consideration rather that he is entitled to his prerogative, that he

introduces his semen, imbued as it is with the spirit and the virtue of

a divine agent, such as, in a moment of time, performs its functions,

and conveys fertility. For, as we see things suddenly set on fire and

blasted by a spark struck from a flint, or the lightning flashing from a

cloud, so equally does the seed of the male instantly affect the female

which it has touched with a kind of contagion, and transfer to her its

prolific quality, by which it renders fruitful in a moment, not only the

eggs, but the uterus also, and the hen herself. For an inflammable

material is not set on fire by the contact of flame more quickly, than

is the hen made pregnant by intercourse with the cock. But what it is

that is transferred from him to her, we shall afterwards find occasion

to speak of, when we treat this matter specially and at greater length.

In the meantime we must remark, that, if it be derived from the soul,

(for whatever is fruitful is probably endowed also with a soul; and we

have said before, that the egg, in Aristotle’s opinion, as well as the

seeds of plants, has a vegetative soul,) that soul, or at all events the

vegetative one, must be communicated as a graft, and transferred from

the male to the female, from the female to the egg, from the egg to the

fœtus; or else be generated in each of these successively by the

contagion of coition.

The subject, nevertheless, seems full of ambiguity; and so Aristotle,

although he allows that the semen of the male has such great virtue,

that a single emission of it suffices for fecundating very many eggs at

the same time, yet, lest this admission should seem to gainsay the

efficacy of frequent repetitions of intercourse, he further says,[240]

“In birds, not even those eggs which arise through intercourse can

greatly increase in size, unless the intercourse be continued; and the

reason of this is, that, as in women, the menstrual excretion is drawn

downwards by sexual intercourse, (for the uterus, becoming warm,

attracts moisture, and its pores are opened,) so also does it happen

with birds, in which the menstrual excrement, because it accumulates

gradually, and is retained above the cincture, and cannot escape, from

being in small quantity, only passes off when it has reached the uterus

itself. For by this is the egg increased, as is the fœtus of the

viviparous animal by that which flows through the umbilicus. For almost

all birds, after but a single act of intercourse, continue to produce

eggs, but they are small.”

Now, so far perhaps would the opinion of Aristotle be correct, that more

and larger eggs are procured by frequently-repeated intercourse;

because, as he says, there may be “a flow of more fruitful material to

the womb, when warmed by the heat of coition;” not however that frequent

coition must necessarily take place in order to render the eggs that are

laid prolific. For experience, as we have said, teaches the contrary,

and the reason which he alleges does not seem convincing; since the

rudiments of eggs are not formed in the uterus from menstrual blood,

which is found in no part of the hen, but in the ovary, where no blood

pre-exists, and originate as well without, as along with the intercourse

of the cock.

The hen, as well as all other females, supplies matter, nutrition, and

place to the conception. The matter, whence the rudiments of all eggs

are produced in the ovary and take their increase, seems to be the very

same from which all the other parts of the hen, namely, the fleshy,

nervous, and bony structures, as well as the head and the rest of the

members, are nourished and grow. Nourishment is in fact conveyed to each

single papula and yelk contained in the ovary by means of vessels, in

the same way precisely as to all the other parts of the hen. But the

place where the egg is provided with membranes, and perfected by the

addition of the chalazæ and shell, is the uterus.

But that the hen neither emits any semen during intercourse, nor sheds

any blood into the cavity of the uterus, and that the egg is not formed

in the mode in which Aristotle supposed a conception to arise, nor, as

physicians imagine, from a mixture of the seminal fluids; as also that

the semen of the cock does not penetrate into, nor is attracted towards,

the cavity of the uterus of the hen, is all made manifestly clear by

this one observation, namely, that after intercourse there is nothing

more to be found in the uterus, than there was before the act. And when

this shall have been afterwards clearly established and demonstrated to

be true of all kinds of animals, which conceive in a uterus, it will at

the same time be equally evident, that what has hitherto been handed

down to us from all antiquity on the generation of animals, is

erroneous; that the fœtus is not constituted of the semen either of the

male or female, nor of a mixture of the two, nor of the menstrual blood,

but that in all animals, as well in the prolific conception as after it,

the same series of phenomena occur as in the generation of the chick

from the egg, and as in the production of plants from the seeds of their

several kinds. For, besides that, it appears the male is not required as

being in himself agent, workman, and efficient cause; nor the female, as

if she supplied the matter; but that each, male as well as female, may

be said to be in some sort the operative and parent; and the fœtus, as a

mixture of both, is created a mixed resemblance and kind. Nor is that

true which Aristotle often affirms, and physicians take for granted,

namely, that immediately after intercourse, something either of the

fœtus or the conception may be found in the uterus, (for instance, the

heart, the “three bullæ,” or some other principal part,) at any rate

_something_--a coagulum, some mixture of the spermatic substances, or

other things of the like kind. On the contrary, it is not till long

after intercourse that the eggs and conception first commence their

existence, among the greater number of animals, and these the most

perfect ones; I mean in the cases where the females have been fruitful

and have become pregnant. And that the female is prolific, before any

conception is contained in the uterus, there are many indications, as

will be hereafter set forth in the history of viviparous animals: the

breasts enlarge, the uterus begins to swell, and by other symptoms a

change of the whole system is discerned.

But the hen, though she have for the most part the rudiments of eggs in

her before intercourse, which are afterwards by this act rendered

fruitful, and there be, therefore, something in her immediately after

coition, yet even when she, as in the case of other animals, has as yet

no eggs ready prepared in the ovary, or has at the time of the

intercourse got rid of all she had, yet does she by and by, even after

some lapse of time, as if in possession of both principles or the powers

of both sexes, generate eggs by herself after the manner of plants; and

these (I speak from experience) not barren, but prolific.

Nay, what is more, if you remove all the eggs from beneath a hen that

has been fecundated and is now sitting, (after having already laid all

her eggs, and no more remain in the ovary,) she will begin to lay again;

and the eggs thus laid will be prolific, and have both principles

inherent in them.

EXERCISE THE FORTY-FIRST.

_Of the sense in which the hen may be called the “prime efficient:” and

of her parturition._

It has already been said, that the hen is the efficient cause of

generation, or an instrument of Nature in this work, not indeed

immediately, or of herself; but when rendered prolific by commission

from, and in virtue of the male. But as the male is considered by

Aristotle to be the first principle of generation on his own merits,

because the first impulse toward generation proceeds from him, so may

the hen in some measure be put down as the first cause of generation;

inasmuch as the male is undoubtedly inflamed to venery by the presence

of the female. “The female fish,” says Pliny,[241] “will follow the male

at the season of intercourse, and strike his belly with her nose; at the

spawning time the male will do the like to the female.” I have myself at

times seen male fishes in shoals following a female that was on the

point of spawning, in the same way as dogs pursue a bitch, that they

might sprinkle the ova just laid with their milk or seed. But this is

particularly to be remarked in the more wanton and lascivious females,

who stir up the dormant fires of Cupid, and inspire a silent love; hence

it is that the common cock, so soon as he sees one of his own hens that

has been absent for ever so short time, or any other stranger-hen,

forthwith feels the sting of desire, and treads her. Moreover,

victorious in a battle, although wounded and tired from the fight, he

straightway sets about treading the wives of his vanquished foe one

after another. And that he may further feed the flame of love thus

kindled in his breast, by various gesticulations, incitements, and

caresses, often crowing the while, calling his hens to him, approaching

and walking round them, and tripping himself with his wings, he entices

his females to intercourse as by a kind of fascination. Such are the

arts of the male; but sometimes a certain sullenness of the female, and

an apparent disinclination on her part, contribute not a little to

arouse the ardour of the male and stimulate his languishing desire, so

that he fills her more quickly and more copiously with prolific spirit.

But of allurements of this kind, and in what degree they promote

conception, we shall speak more hereafter. For, if you carefully weigh

the works of nature, you will find that nothing in them was made in

vain, but that all things were ordered with a purpose and for the sake

of some good end.

Almost all females, though they have pleasure in the act of intercourse

and impregnation, suffer pain in parturition. But the reverse is the

case with the hen, who loudly complains during intercourse and struggles

against it; but in parturition, although the egg be very large in

comparison with the body and the orifice of the uterus, and it does

nothing to further its exit, (as is customary with the young of

viviparous animals,) yet she brings forth easily and without pain, and

immediately afterwards commences her exultations; and with her loud

cackling calls the cock as it seems to share in her triumph.

But, although many rudiments of eggs are found in the hen’s ovary, of

various sizes and in different stages, so that some are larger and

nearer to maturity than others, yet all of them appear to be fecundated,

or to receive the prolific faculty from the tread of the cock at the

same time and in the same degree. And though a considerable time elapse

(namely, thirty or more days) before the common hen or hen-partridge lay

all the eggs which she has conceived, yet in a stated time after the

mother has begun to sit upon them (say twenty or two and twenty days)

all the young are hatched nearly at the same time; nor are they less

perfect than if they had commenced their origin simultaneously, from the

period of one and the same conception, as the whelps of bitches do.

And while we are here, and while I think how small are the prolific

germs of eggs, mere papulæ and exudations less than millet-seeds, and

contemplate the full proportions of the cock that springs from thence,

his fine spirit, and his handsome plumage, I cannot but express my

admiration that such strength should be reposed in the nature of things

in such insignificant elements, and that it has pleased the omnipotent

Creator out of the smallest beginnings to exhibit some of his greatest

works. From a minute and scarce perceptible papula springs the hen, or

the cock, a proud and magnificent creature. From a small seed springs a

mighty tree; from the minute gemmule or apex of the acorn, how wide does

the gnarled oak at length extend his arms, how loftily does he lift his

branches to the sky, how deeply do his roots strike down into the

ground! “It is in truth a great miracle of nature,” says Pliny,[242]

“that from so small an origin is produced a material that resists the

axe, and that supplies beams, masts, and battering-rams. Such is the

strength, such the power of nature!” But in the seeds of all plants

there is a gemmule or bud of such a kind, so small that if the top

only, a very point, be lost, all hope of propagation is immediately

destroyed; in so small a particle does all the plastic power of the

future tree seem lodged! The provident ant by gnawing off this little

particle stores safely in her subterraneous hoard the grain and other

seeds she gathers, and ingeniously guards against their growing: “The

cypress,” adds Pliny, in the same place, “bears a seed that is greatly

sought after by the ant; which makes us still further wonder, that the

birth of mighty trees should be consumed in the food of so small an

animal.” But on these points we shall say more when we show that many

animals, especially insects, arise and are propagated from elements and

seeds so small as to be invisible, (like atoms flying in the air,)

scattered and dispersed here and there by the winds; and yet these

animals are supposed to have arisen spontaneously, or from

decomposition, because their ova are nowhere to be found. These

considerations, however, may furnish arguments to that school of

philosophy which teaches that all things are produced from nothing; and

indeed there is hardly any ascertainable proportion between the rudiment

and the full growth of any animal.

Nor should we so much wonder what it is in the cock that preserves and

governs so perfect and beautiful an animal, and is the first cause of

that entity which we call the soul; but much more, what it is in the

egg, aye, in the germ of the egg, of so great virtue as to produce such

an animal, and raise him to the very summit of excellence. Nor are we

only to admire the greatness of the artificer that aids in the

production of so noble a work, but chiefly the “contagion” of

intercourse, an act which is so momentary! What is it, for instance,

that passes from the male into the female, from the female into the egg,

from the egg into the chick? What is this transitory thing, which is

neither to be found remaining, nor touching, nor contained, as far as

the senses inform us, and yet works with the highest intelligence and

foresight, beyond all art; and which, even after it has vanished,

renders the egg prolific, not because it now touches, but because it

formerly did so, and that not merely in the case of the perfect and

completed egg, but of the imperfect and commencing one when it was yet

but a speck; aye, and makes the hen herself fruitful before she has yet

produced any germs of eggs, and this too so suddenly, as if it were

said by the Almighty, “Let there be progeny,” and straight it is so?

Let physicians, therefore, cease to wonder at what always excites their

astonishment, namely, the manner in which epidemic, contagious, and

pestilential diseases scatter their seeds, and are propagated to a

distance through the air, or by some ‘fomes’ producing diseases like

themselves, in bodies of a different nature, and in a hidden fashion

silently multiplying themselves by a kind of generation, until they

become so fatal, and with the permission of the Deity spread destruction

far and wide among man and beast; since they will find far greater

wonders than these taking place daily in the generation of animals. For

agents in greater number and of more efficiency are required in the

construction and preservation of an animal, than for its destruction;

since the things that are difficult and slow of growth, decay with ease

and rapidity. Seneca[243] observes, with his usual elegance, “How long a

time is needed for conception to be carried out to parturition! with

what labour and tenderness is an infant reared! to what diligent and

continued nutrition must the body be subject, to arrive at adolescence!

but by what a nothing is it destroyed! It takes an age to establish

cities, an hour to destroy them. By great watching are all things

established and made to flourish, quickly and of a sudden do they fall

in pieces. That which becomes by long growth a forest, quickly, in the

smallest interval of time, and by a spark, is reduced to ashes.” Nor is

even a spark necessary, since by the solar rays transmitted through a

small piece of glass and concentrated to a focus, fire may be

immediately produced, and the largest things be set in flames. So easy

is every thing to nature’s majesty, who uses her strength sparingly, and

dispenses it with caution and foresight for the commencement of her

works by imperceptible additions, but hastens to decay with suddenness

and in full career. In the generation of things is seen the most

excellent, the eternal and almighty God, the divinity of nature, worthy

to be looked up to with reverence; but all mortal things run to

destruction of their own accord in a thousand ways.

EXERCISE THE FORTY-SECOND.

_Of the manner in which the generation of the chick takes place from the

egg._

Hitherto we have considered the egg as the fruit and end; it still

remains for us to treat of it as the seed and beginning. “We must now

inquire,” says Fabricius[244], “how the generation of the chick results

from the egg, setting out from that principle of Aristotle and Galen,

which is, even conceded by all, to wit, that all things which are made

in this life, are manifestly made by these three: workers, instruments,

and matter.”

But since in natural phenomena, the work is not extrinsic, but is

included in the matter, or the instruments, he concludes that we must

take cognizance only of the agent and the matter.

As we are here about to shew in what manner the chick arises from the

egg, however, I think it may be of advantage for me to preface this, by

showing the number of modes in which one thing may be said to be made

from another.

For so it will appear, more clearly and distinctly, after which of these

generation takes place in the egg, and what are the right conclusions in

regard to its matter, its instruments, and efficient cause.

Aristotle[245] has laid down that there are four modes in which one

thing is made from another: “first, when we say that from day night is

made, or from a boy a man, since one is after the other; secondly, when

we say that a statue is made from brass, or a bed from wood, or any

thing else from a certain material, so that the whole consists of

something, which is inherent and made into a form; thirdly, as when from

a musical man is made an unmusical one, or from a healthy, a sick one,

or contraries in any way: fourthly, as Epicharmus exaggerates it, as of

calumnies, cursing; of cursing, fighting. But all these are to be

referred to that from whence the movement took its rise; for the calumny

is a certain portion of the whole quarrel. Since then these are the

methods in which one thing is made from another, it is clear that the

seed is in one of two of these. For that which is born arises out of it,

either as from matter, or as from the prime mover. For it is not, ‘as

this is after that,’ in the same way as after the Panathenœa navigation;

nor as ‘one contrary from another,’ for in such case, a thing would be

born out of its contrary, because it is in a state of decay, and there

must be something else as subject matter.”

By these words, Aristotle rightly infers, that the semen proceeding from

the male, is the efficient or instrumental cause of the embryo; since it

is no part of what is born, either in the first or third manner;

(namely, as one thing is after another, or as it is out of its

contrary;) nor does it arise from the subject matter.

But then, as he adds, in the same place, “that which comes out of the

male in coition, is not with truth and propriety called semen, but

rather geniture; and it is different from the seed properly so called.

For that is called the geniture which, proceeding from the generant, is

the cause which first promotes the beginning of generation. I mean in

those creatures, which nature designed to have connection; but the seed

is that which derives its origin from the intercourse of the two (i. e.

of the male and female); such is the seed of all plants; and of some

animals in which the sex is not distinct; it is the produce, as it were,

of the male and female mixed together originally, like a kind of

promiscuous conception;” and such as we have formerly in our history

declared the egg to be, which is called both fruit and seed. For the

seed and the fruit are distinct from each other, and in the relation of

antecedent and consequent; the fruit is that which is out of something

else, the seed is that out of which something else comes; otherwise both

were the same.

It remains then, to inquire, in how many of the aforesaid ways the fœtus

may arise, not indeed from the geniture of the male, but out of the true

seed, or out of the egg or conception, which is in reality the seed of

animals.

EXERCISE THE FORTY-THIRD.

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

It is admitted, then, that the fœtus is formed from a prolific egg, as

out of the proper matter, and as it were by the requisite agency, and

that the same egg stands for both causes of the chick. For inasmuch as

it derives its origin from the hen, and is considered as a fruit, it is

the matter: but, in so far as it contains in its whole structure the

prolific and plastic faculty infused by the male, it is called the

efficient cause of the chick.

Moreover, not only as Fabricius supposed, are these, namely, the agent

and the instrument, inseparably joined in one and the same egg, but it

is also necessary, that the aliment by which the chick is nourished, be

present in the same place. Indeed, in the prolific egg, these four are

found together, to wit, the agent, the instrument, the matter, and the

aliment, as we have shown in our history.

Wherefore, we say, that the chick is formed from the prolific egg in all

the aforesaid ways, namely, as from matter, by an efficient, and by an

instrument; and moreover, as a man grows out of a boy, as the whole is

made up of its parts, and as a thing grows from its nutriment; a

contrary thing springs from a contrary.

For after incubation is begun, as soon as by the internal motive

principle a certain clear liquid which we have called the eye of the egg

is produced, we say that that liquid is made as it were out of a

contrary; in the same way as we suppose the chyle through concoction to

be formed out of its contraries, (namely, crude articles of food,) and

in the same way as we are said to be nourished by contraries; so, from

the albumen is formed and augmented that to which we have given the

names of the eye and the colliquament; and in the same manner, from that

clear fluid do the blood and pulsating vesicle, the first particles of

the chick, receive their being, nutrition, and growth. The nutriment, I

say, is by the powers of an inherent and innate heat, assimilated by

means of concoction, as it were out of a contrary. For the crude and

unconcocted are contrary to the concocted and assimilated, as the

unmusical man is to the musical, and the sick to the sound man.

And when the blood is engendered from the clear colliquament, or a clear

fluid is produced from the white or the yelk, there is generation as

regards the former, corruption as regards the latter; a transmutation,

namely, is made from the extremes of contraries, the subject-matter all

the while remaining the same. To explain: by the breaking up of the

first form of the white, the colliquament is produced; and from the

consumption of this colliquament, follows the form of the blood, in the

same way precisely as food is converted into the substance of the thing

fed.

It is thus, then, that the chick is said to be made out of the egg, as

it were by a contrary; for in the nutrition and growth of the chick in

the egg, white and yelk are equally broken up and consumed, and finally

the whole substance of the egg. It is clear, therefore, that the chick

is formed from the egg, as it were by a contrary, namely the aliment,

and as if by an abstraction, and from a non-entity. For the first

particle of the chick, viz.: the blood or punctum saliens, is

constituted out of something which is not blood, and altogether its

contrary, the same subject-matter always remaining.

The chick too is made from the egg, as a man is made from a boy. For in

the same way, as out of plants seeds arise, and out of seeds, buds,

sprouts, stems, flowers, and fruits; so also out of the egg, the seed of

the hen is produced, the dilatation of the cicatricula and the

colliquament, the blood and the heart, as the first particle of the

fœtus or fruit; and all this, in the same way as the day from the night,

the summer from the spring, a man from a boy--one follows or comes after

the other. So that, in the same way as fruits arise after flowers on the

same stem, so likewise is the colliquament formed after the egg, the

blood after this, as from the primogeneous humour, the chick after the

blood, and out of it, as the whole out of a part; in the same way, as by

Epicharmus’s exaggeration, out of calumnies comes cursing, and out of

cursing fighting. For the blood first begins its existence with the

punctum saliens, and at the same time, seems to be as well a part of the

chick, and a kind of efficient or instrument of its generation,

inseparable, as Fabricius thinks, from the agent. But how the egg may be

called the efficient and instrument of generation, has partly been

explained already, and will be illustrated more copiously by what we

shall presently say.

So much has been fully established in our history, that the punctum

pulsans and the blood, in the course of their growth, attach round

themselves the rest of the body, and all the other members of the chick,

just as the yelk in the uterus, after being evolved from the ovary,

surrounds itself with the white; and this not without concoction and

nutrition. Now the common instrument of all vegetative operations, is,

in the opinion of all men, an internal heat or calidum innatum, or a

spirit diffused through the whole, and in that spirit a soul or faculty

of a soul. The egg, therefore, beyond all doubt, has its own operative

soul, which is all in the whole, and all in each individual part, and

contains within itself a spirit or animal heat, the immediate instrument

of that soul. To one who should ask then, how the chick is made from the

egg, we answer: after all the ways recited by Aristotle, and devised by

others, in which it is possible for one thing to be made from another.

EXERCISE THE FORTY-FOURTH.

_Fabricius is mistaken with regard to the matter of the generation of

the chick in ovo._

As I proposed to myself at the outset, I continue to follow Fabricius as

pointing out the way; and we shall, therefore, consider the three things

which he says are to be particularly regarded in the generation of the

chick, viz.: the agent, the matter, and the nourishment of the embryo.

These must needs be all contained in the egg; he proposes various doubts

or questions, and quotes the opinions of the most weighty authorities in

regard to them, these opinions being frequently discordant. The first

difficulty is in reference to the matter and nourishment of the chick.

Hippocrates,[246] Anaxagoras, Alcmaeon, Menander, and the ancient

philosophers, all thought that the chick was engendered from the

vitellus, and was nourished by the albumen. Aristotle,[247] however, and

after him, Pliny,[248] maintained, on the contrary, that the chick was

incorporated from the albumen, and nourished by the vitellus. But

Fabricius himself, will have it that neither the white nor yelk forms

the matter of the chick; he strives to combat both of the preceding

opinions, and teaches that the white and the yellow alike do no more

than nourish the chick. One of his arguments, amongst a great number of

others which I think are less to be acquiesced in, appears to me to have

some force. The branches of the umbilical vessels, he says, through

which the embryo undoubtedly imbibes its nourishment, are distributed to

the albumen and the vitellus alike, and both of these fluids diminish as

the chick grows. And it is on this ground, that Fabricius in

confirmation of his opinion, says[249]: “Of the bodies constituting the

egg, and adapted to forward the generation of the chick, there are only

three, the albumen, the vitellus, and the chalazæ; now the albumen and

vitellus are the nourishment of the chick; so that the chalazæ alone

remain as matter from which it can be produced.”

Nevertheless, that the excellent Fabricius is in error here, we have

demonstrated above in our history. For after the chick is already almost

perfected, and its head and its eyes are distinctly visible, the chalazæ

can readily be found entire, far from the embryo, and pushed from the

apices towards the sides: the office of these bodies, as Fabricius

himself admits, is that of ligaments, and to preserve the vitellus in

its proper position within the albumen. Nor is that true, which

Fabricius adds in confirmation of his opinion, namely, that the chalazæ

are situated in the direction of the blunt part of the egg. For after

even a single day’s incubation, the relative positions of the fluids of

the egg are changed, the yelk being drawn upwards, and the chalazæ on

either hand removed, as we have already had occasion to say.

He is also mistaken when he speaks of the chalazæ, as proper parts of

the egg. The egg consists in fact but of white and yelk; the chalazæ as

well as the membranes, are mere appendages of the albumen and vitellus.

The chalazæ, in particular, are the extremities of certain membranes,

twisted and knotted; they are produced in the same way as a rope is

formed by the contortion of its component filaments, and exist for the

purpose of more certainly securing the several elements of the egg in

their respective places.

Fabricius, therefore, reasons ill when he says, that “the chalazæ are

found in the part of the egg where the embryo is produced, wherefore it

is engendered from them;” for even on his own showing, this could never

take place, he admitting that the chalazæ are extant in either extremity

of the egg, whilst the chick never makes its appearance save at the

blunt end; in which, moreover, at the first commencement of generation,

no chalaza can be seen. Farther, if you examine the matter in a fresh

egg, you will find the superior chalaza not immediately under the blunt

end or its cavity, but declined somewhat to the side; not to that side,

however, where the cavity is extending, but rather to the opposite side.

Still farther, from what has preceded, it is obvious that the relative

positions of the fluids of the egg are altered immediately that

incubation is begun: the eye increased by the colliquament is drawn up

towards the cavity in the blunt end of the egg, whence the white and the

chalaza are on either hand withdrawn to the side. For the macula or

cicatricula which before incubation was situated midway between the two

ends, now increased into the eye of the egg, adjoins the cavity in the

blunt end, and whilst one of the chalazæ is depressed from the blunt

end, the other is raised from the sharp end, in the same way as the

poles of a globe are situated when the axis is set obliquely; the

greater portion of the albumen, particularly that which is thicker,

subsides at the same time, into the sharp end.

Neither is it correct to say, that the chalazæ bear a resemblance in

length and configuration to the chick on its first formation, and that

the number of their nodules corresponds with the number of the principal

parts of the embryo; a statement which gives Fabricius an opportunity of

adducing an argument connected with the _matter_ of the chick, based on

the similarity of its consistency to that of the chalazæ. But the red

mass (which Fabricius regarded as the liver) is neither situated in nor

near the chalaza, but in the middle of the clear colliquament; and it is

not any rudiment of the liver but of the heart alone. Neither does his

view square with the example he quotes of the tadpole, “of which,” he

says, “there is nothing to be seen but the head and the tail, that is to

say, the head and spine, without a trace of upper or lower extremities.”

And he adds, “he who has seen a chalaza, and this kind of conception, in

so far as the body is concerned, will believe that in the former, he has

already seen the latter.” I, however, have frequently dissected the

tadpole, and have found the belly of large size, and containing

intestines and liver and heart pulsating; I have also distinguished the

head and the eyes. The part which Fabricius takes for the head, is the

rounded mass [or entire body] of the tadpole, whence the creature is

called ‘gyrinus,’ from its circular form. It has a tail with which it

swims, but is without legs. About the epoch of the summer solstice, it

loses the tail, when the extremities begin to sprout. Nothing however

occurs in the nature of a division of the embryo pullet into the head

and spine, which should induce us to regard it as produced from the

chalazæ, and in the same manner as the tadpole.

The position and fame of Fabricius, however, a man exceedingly well

skilled in anatomy, do not allow me to push this refutation farther. Nor

indeed, is there any necessity so to do, seeing that the thing is so

clearly exhibited in our history.

Our author concludes, by stating that his opinion is of great antiquity,

and was in vogue even in the times of Aristotle.

For my own part, nevertheless, I regard the view of Ulysses Aldrovandus

as the older, he maintaining, that the chalazæ are the spermatic fluid

of the cock, from which and through which alike the chick is engendered.

Neither notion, however, is founded on fact, but is the popular error of

all times: the chalazæ, treads, or treadles, as our English name

implies, are still regarded by the country folks as the semen of the

cock.

“The treadles (grandines),” says Aldrovandus; “are the spermatic fluid

of the cock, because no fertile egg is without them.” But neither is any

unprolific egg without these parts, a fact which Aldrovandus was either

ignorant of or concealed. Fabricius admits this fact; but though he has

denied that the semen of the male penetrates to the uterus or is ever

found in the egg, he nevertheless, contends, that the chalazæ alone of

all the parts of the egg are impregnated with the prolific power of the

egg, and are the repositories of the fecundating influence; and this,

with the fact staring him in the face all the while, that there is no

perceptible difference between the chalazæ of a prolific and an

unprolific egg. And when he admits, that the mere rudiments of eggs in

the ovary, as well as the vitelli that are surrounded with albumen,

become fecundated through the intercourse of the cock, I conceive that

this must have been the cause of the error committed by so distinguished

an individual. It was the current opinion, as I have said oftener than

once, both among philosophers and physicians, that the matter of the

embryo in animal generation, was the geniture, either of the male, or of

the female, or resulted from a mixture of the two, and that from this,

deposited in the uterus, like a seed in the ground, which produces a

plant, the animal was engendered. Aristotle, himself, is not very far

from the same view, when he maintains the menstrual blood of the female

to be the seed, which the semen of the male coagulates, and so composes

the conception.

The error which we have announced, having been admitted by all in former

times, as a matter of certainty, it is not to be wondered at, that

various erroneous opinions based on each man’s conjecture, should have

emanated from it. They, however, are wholly mistaken, who fancy that

anything in the shape of a ‘prepared or fit matter’ must necessarily

remain in the uterus after intercourse, from which the fœtus is

produced, or the first conception is formed, or that anything is

immediately fashioned in the uterine cavity that corresponds to the seed

of a plant deposited in the bosom of the ground. For it is quite

certain, that in the uterus of the fowl, and the same thing is true of

the uterus of every other female animal, there is nothing discoverable

after intercourse more than there was before it.

It appears, consequently, that Fabricius erred when he said:[250] “In

the same way as a viviparous animal is incorporated from a small

quantity of seminal matter, whilst the matter which is taken up as food

and nourishment is very large; so a small chalaza suffices for the

generation of a chick, and the rest of the matter contained in the egg

goes to it in the shape of nutriment.” From which it is obvious, that he

sought for some such ‘prepared matter’ in the egg, whence the chick

should be incorporated; mainly, as it seems, that he might not be found

in contradiction with Aristotle’s definition of an egg,[251] viz.: as

“that from part of which an animal is engendered; and the remainder of

which is food for the thing engendered.” This of Fabricius, therefore,

has the look of a valid argument, namely, “Since there are only three

parts in the egg,--the albumen, the vitellus, and the chalazæ; and the

two former alone supply aliment; it necessarily follows, that the

chalazæ alone are the matter from which the chick is constituted.”

Thus, our learned anatomist, blinded by a popular error, seeking in the

egg for some particular matter fitted to engender the chick distinct

from the rest of the contents of the egg, has gone astray. And so it

happens to all, who forsaking the light, which the frequent dissection

of bodies, and familiar converse with nature supplies, expect that they

are to understand from conjecture, and arguments founded on

probabilities, or the authority of writers, the things or the facts

which they ought themselves to behold with their own eyes, to perceive

with their proper senses. It is not wonderful, therefore, when we see

that we have so many errors accredited by general consent, handed down

to us from remote antiquity, that men otherwise of great ingenuity,

should be egregiously deceived, which they may very well be, when they

are satisfied with taking their knowledge from books, and keeping their

memory stored with the notions of learned men. They who philosophise in

this way, by tradition, if I may so say, know no better than the books

they keep by them.

In the egg then, as we have said, there is no distinct part or prepared

matter present, from which the fœtus is formed; but in the same way as

the apex or gemmule protrudes in a seed; so in the egg, there is a

macula or cicatricula, which endowed with plastic power, grows into the

eye of the egg and the colliquament, from which and in which the

primordial or rudimentary parts of the chick, the blood, to wit, and the

punctum saliens are engendered, nourished, and augmented, until the

perfect chick is developed. Neither is Aristotle’s definition of an egg

correct, as a body from part of which an embryo is formed, and by part

of which it is nourished, unless the philosopher is to be understood in

the following manner: The egg is a body, from part of which the chick

arises, not as from a special matter, but as a man grows out of a boy;

or an egg is a perfect conception from which the chick is said to be

partly constituted, partly nourished; or to conclude, an egg is a body,

the fluids of which serve both for the matter and the nourishment of the

parts of the fœtus. In this sense, indeed, Aristotle[252] teaches us

that the matter of the human fœtus is the menstrual blood; “which (when

poured into the uterus by the veins) nature employs to a new purpose;

viz., that of generation, and that a future being may arise, such as the

one from which it springs; for potentially it is already such as is the

body whose secretion it is, namely, the mother.”

EXERCISE THE FORTY-FIFTH.

_What is the material of the chick, and how is it formed in the egg?_

Since, then, we are of opinion, that for the acquisition of truth, we

cannot rely on the theories of others, whether these rest on mere

assertions, or even may have been confirmed by plausible arguments,

except there be added thereto a diligent course of observation; we

propose to show, by clearly-arranged remarks derived from the book of

nature, what is the material of the fœtus, and in what manner it thence

takes its origin. We have seen that one thing is made out of another

(tanquam ex materia) in two ways, and this as well in works of art, as

in those of nature, and more particularly in the generation of animals.

One of these ways, viz., when the object is made out of something

pre-existing, is exemplified by the formation of a bed out of wood, or a

statue from stone; in which case, the whole material of the future piece

of work has already been in existence, before it is finished into form,

or any part of the work is yet begun; the second method is, when the

material is both made and brought into form at the same time. Just then

as the works of art are accomplished in two manners, one, in which the

workman cuts the material already prepared, divides it, and rejects what

is superfluous, till he leaves it in the desired shape (as is the custom

of the statuary); the other, as when the potter educes a form out of

clay by the addition of parts, or increasing its mass, and giving it a

figure, at the same time that he provides the material, which he

prepares, adapts, and applies to his work; (and in this point of view,

the form may be said rather to have been _made_ than _educed_;) so

exactly is it with regard to the generation of animals.

Some, out of a material previously concocted, and that has already

attained its bulk, receive their forms and transfigurations; and all

their parts are fashioned simultaneously, each with its distinctive

characteristic, by the process called metamorphosis, and in this way a

perfect animal is at once born; on the other hand, there are some in

which one part is made before another, and then from the same material,

afterwards receive at once nutrition, bulk, and form: that is to say,

they have some parts made before, some after others, and these are at

the same time increased in size and altered in form. The structure of

these animals commences from some one part as its nucleus and origin, by

the instrumentality of which the rest of the limbs are joined on, and

this we say takes place by the method of epigenesis, namely, by degrees,

part after part; and this is, in preference to the other mode,

generation properly so called.

In the former of the ways mentioned, the generation of insects is

effected where by metamorphosis a worm is born from an egg; or out of a

putrescent material, the drying of a moist substance or the moistening

of a dry one, rudiments are created, from which, as from a caterpillar

grown to its full size, or from an aurelia, springs a butterfly or fly

already of a proper size, which never attains to any larger growth

after it is first born; this is called metamorphosis. But the more

perfect animals with red blood are made by epigenesis, or the

superaddition of parts. In the former, chance or hazard seems the

principal promoter of generation, and there, the form is due to the

potency of a preexisting material; and the first cause of generation is

‘matter,’ rather than ‘an external efficient;’ whence it happens too

that these animals are less perfect, less preservative of their own

races, and less abiding, than the red-blooded terrestrial or aquatic

animals, which owe their immortality to one constant source, viz. the

perpetuation of the same species; of this circumstance we assign the

first cause to nature and the vegetative faculty.

Some animals then are born of their own accord, concocted out of matter

spontaneously, or by chance, as Aristotle seems to assert, when he

speaks of animals whose matter is capable of receiving an impulse from

itself, viz. the same impulse given by hazard, as is attributable to the

seed, in the generation of other animals. And the same thing happens in

art, as in the generation of animals. Some things, which are the result

of art, are so likewise of chance, as good health; others always owe

their existence to art; for instance, a house. Bees, wasps, butterflies,

and whatever is generated from caterpillars by metamorphosis, are said

to have sprung from chance, and therefore to be not preservative of

their own race; the contrary is the case with the lion and the cock;

they owe their existence as it were to nature or an operative faculty of

a divine quality, and require for their propagation an identity of

species, rather than any supply of fitting material.

In the generation by metamorphosis forms are created as if by the

impression of a seal, or, as if they were adjusted in a mould; in truth

the whole material is transformed. But an animal which is created by

epigenesis attracts, prepares, elaborates, and makes use of the

material, all at the same time; the processes of formation and growth

are simultaneous. In the former the plastic force cuts up, and

distributes, and reduces into limbs the same homogeneous material; and

makes out of a homogeneous material organs which are dissimilar. But in

the latter, while it creates in succession parts which are differently

and variously distributed, it requires and makes a material which is

also various in its nature, and variously distributed, and such as is

now adapted to the formation of one part, now of another; on which

account we believe the perfect hen’s-egg to be constituted of various

parts.

Now it appears clear from my history, that the generation of the chick

from the egg is the result of epigenesis, rather than of metamorphosis,

and that all its parts are not fashioned simultaneously, but emerge in

their due succession and order; it appears, too, that its form proceeds

simultaneously with its growth, and its growth with its form; also that

the generation of some parts supervenes on others previously existing,

from which they become distinct; lastly, that its origin, growth, and

consummation are brought about by the method of nutrition; and that at

length the fœtus is thus produced. For the formative faculty of the

chick rather acquires and prepares its own material for itself than only

finds it when prepared, and the chick seems to be formed and to receive

its growth from no other than itself. And, as all things receive their

growth from the same power by which they are created, so likewise should

we believe, that by the same power by which the chick is preserved, and

caused to grow from the commencement, (whether that may have been the

soul or a faculty of the soul,) by that power, I say, is it also

created. For the same efficient and conservative faculty is found in the

egg as in the chick; and of the same material of which it constitutes

the first particle of the chick, out of the very same does it nourish,

increase, and superadd all the other parts. Lastly, in generation by

metamorphosis the whole is distributed and separated _into_ parts; but

in that by epigenesis the whole is put together _out of_ parts in a

certain order, and constituted _from_ them.

Wherefore Fabricius was in error when he looked for the material of the

chick, (as a distinct part of the egg, from which its body was formed,)

as if the chick were created by metamorphosis, or a transformation of

the material in mass; and as if all, or at least the principal parts of

the body sprang from the same material, and, to use his own words, were

incorporated simultaneously. [He is, therefore, of course opposed to the

notion] of the chick being formed by epigenesis, in which a certain

order is observed according to the dignity and the use of parts, where

at first a small foundation is, as it were, laid, which, in the course

of growth, has at one and the same time distinct structures formed and

its figure established, and acquires an additional birth of parts

afterwards, each in its own order; in the same way, for instance, as the

bud bursting from the top of the acorn, in the course of its growth, has

its parts separately taking the form of root, wood, pith, bark, boughs,

branches, leaves, flowers, and fruit, until at length out comes a

perfect tree; just so is it with the creation of the chick in the egg:

the little cicatrix, or small spot, the foundation of the future

structure, grows into the eye and is at the same time separated into the

colliquament; in the centre of which the punctum sanguineum pulsans

commences its being, together with the ramification of the veins; to

these is presently added the nebula, and the first concretion of the

future body; this also, in proportion as its bulk increases, is

gradually divided and distinguished into parts, which however do not all

emerge at the same time, but one after the other, and each in its proper

order. To conclude, then: in the generation of those animals which are

created by epigenesis, and are formed in parts, (as the chick in the

egg,) we need not seek one material for the incorporation of the fœtus,

another for its commencing nutrition and growth; for it receives such

nutrition and growth from the same material out of which it is made;

and, vice versâ, the chick in the egg is constituted out of the

materials of its nutrition and growth. And an animal which is capable of

nutrition is of the same potency as one which is augmentative, as we

shall afterwards show; and they differ only, as Aristotle says, in their

distinctness of being; in all other respects they are alike. For, in so

far as anything is convertible into a substance, it is nutritious, and

under certain conditions it is augmentative: in virtue of its repairing

a loss of substance, it is called nutriment, in virtue of its being

added, where there is no such loss of substance, it is called increment.

Now the material of the chick, in the processes of generation,

nutrition, and augmentation is equally to be considered as aliment and

increment. We say simply that anything is generated, when no part of it

has pre-existed; we speak of its being nourished and growing when it has

already existed. The part of the fœtus which is first formed is said to

be begotten or born; all substitutions or additions are called

adnascent, or aggenerate. In all there is the same transmutation or

generation from the same to the same; as concerns a part, this is

performed by the process of nutrition and augmentation, but as regards

the whole, by simple generation; in other respects the same processes

occur equally. For from the same source from which the material first

takes its existence, from that source also does it gain nutriment and

increase. Moreover, from what we shall presently say, it will be made

clear that all the parts of the body are nourished by a common

nutritious juice; for, as all plants arise from one and the same common

nutriment, (whether it be dew or a moisture from the earth,) altered and

concocted in a diversity of manners, by which they are also nourished

and grow; so likewise to identical fluids of the egg, namely, the

albumen and the yelk, do the whole chick and each of its parts owe their

birth and growth.

We will explain, also, what are the animals whose generation takes place

by metamorphosis, and of what kind is the pre-existent material of

insects which take their origin from a worm or a caterpillar; a material

from which, by transmutation alone, all their parts are simultaneously

constituted and embodied, and a perfect animal is born; likewise, to

what animals any constant order in the successive generation of their

parts attaches, as is the case with such as are at first born in an

imperfect condition, and afterwards grow to maturity and perfection; and

this happens to all those that are born from an egg. As in these the

processes of growth and formation are carried on at the same time, and a

separation and distinction of parts takes place in a regularly observed

order, so in their case is there no immediate pre-existing material

present, for the incorporation of the fœtus, (such as the mixture of the

semina of the male and female is generally thought to be, or the

menstrual blood, or some very small portion of the egg,) but as soon as

ever the material is created and prepared, so soon are growth and form

commenced; the nutriment is immediately accompanied by the presence of

that which it has to feed. And this kind of generation is the result of

epigenesis as the man proceeds from the boy; the edifice of the body, to

wit, is raised on the punctum saliens as a foundation; as a ship is made

from a keel, and as a potter makes a vessel, as the carpenter forms a

footstool out of a piece of wood, or a statuary his statue from a block

of marble. For out of the same material from which the first part of the

chick or its smallest particle springs, from the very same is the whole

chick born; whence the first little drop of blood, thence also proceeds

its whole mass by means of generation in the egg; nor is there any

difference between the elements which constitute and form the limbs or

organs of the body, and those out of which all their similar parts, to

wit, the skin, the flesh, veins, membranes, nerves, cartilages, and

bones, derive their origin. For the part which was at first soft and

fleshy, afterwards, in the course of its growth, and without any change

in the matter of nutrition, becomes a nerve, a ligament, a tendon; what

was a simple membrane becomes an investing tunic; what had been

cartilage is afterwards found to be a spinous process of bone, all

variously diversified out of the same similar material. For a similar

organic body (which the vulgar believe to consist of the elements) is

not created out of elements at first existing separately, and then put

together, united, and altered; nor is it put together out of constituent

parts; but, from a transmutation of it when in a mixed state, another

compound is created: to take an instance, from the colliquament the

blood is formed, from the blood the structure of the body arises, which

appears to be homogeneous in the beginning, and resembles the spermatic

jelly; but from this the parts are at first delineated by an obscure

division, and afterwards become separate and distinct organs.

Those parts, I say, are not made similar by any successive union of

dissimilar and heterogeneous elements, but spring out of a similar

material through the process of generation, have their different

elements assigned to them by the same process, and are made dissimilar.

Just as if the whole chick was created by a command to this effect, of

the Divine Architect: “let there be a similar colourless mass, and let

it be divided into parts and made to increase, and in the meantime,

while it is growing, let there be a separation and delineation of parts;

and let this part be harder, and denser, and more glistening, that be

softer and more coloured,” and it was so. Now it is in this very manner

that the structure of the chick in the egg goes on day by day; all its

parts are formed, nourished, and augmented out of the same material.

First, from the spine arise the sides, and the bones are

distinguishable from the flesh by minute lines of extreme whiteness; in

the head three bullæ are perceived, full of crystalline fluid, which

correspond to the brain, the cerebellum, and one eye, easily observable

by a black speck; the substance which at first appears a milky coagulum,

afterwards gradually becomes cartilaginous, has spinous processes

attached to it, and ends in being completely osseous; what was at first

of a mucous nature and colourless, is converted at length into red flesh

and parenchyma; what was at one time limpid and perfectly pure water,

presently assumes the form of brain, cerebellum, and eyes. For there is

a greater and more divine mystery in the generation of animals, than the

simple collecting together, alteration, and composition of a whole out

of parts would seem to imply; inasmuch as here the whole has a separate

constitution and existence before its parts, the mixture before the

elements. But of this more at another time, when we come to specify the

causes of these things.

EXERCISE THE FORTY-SIXTH.

_Of the efficient cause of the generation of the chick and fœtus._

We have thus far spoken of the matter from which the chick in ovo is

generated. We have still with Fabricius to say a few words on the

efficient cause of the chick. As this subject is surrounded with

difficulties, however; as writers nowhere else dispute more virulently

or more wordily, and Aristotle himself in explaining the matter is

singularly intricate and perplexed, and as various questions that can by

no means be lightly treated do in fact present themselves for

consideration, I conceive that I shall be undertaking a task worthy of

the toil if, as I have done in the disquisition on the “matter,” I set

out here by stating in how many ways anything can be said to be

“efficient” or “effective.” We shall thus obtain a clearer idea of what

it is which we are to inquire after under the name of “efficient,” and

further, what estimate we are to form of the ideas of writers upon this

subject; it will at the same time appear from our observations what is

truly and properly to be called “an efficient.”

Aristotle[253] defines an efficient cause to be that “whence is derived

the first principle of change or quiescence; as a counsel, a father; and

simply as doing that which is done; the transmute of the thing

transmuted.” In the generation of animals accordingly many and various

kinds of cause inducing motion are brought forward; sometimes an

accident or quality is assigned; and so animal heat and the formative

faculty are called efficient causes. Sometimes it is an external

substance, previously existing, in which inheres the plastic force or

formative faculty that is designated in the same way; as the cock or his

seminal fluid, by the influence of which the chick is procreated from

the egg. Occasionally it is some internal substance, self-existent, such

as spirit, or innate heat. And again, it is some other substance, such

as form, or nature, or soul, or some portion of the vegetative soul,

that is regarded as the efficient, such a principle as we have already

declared to inhere in the egg.

Besides, since one thing whence motion proceeds is nearer and another

more remote, it sometimes happens that the media between the prime

efficient and the thing last effected, and instruments are regarded as

efficient causes; subordinate conclusions, likewise, or the principles

of subsequents, are reckoned among the number of efficient causes; in

this way some parts are themselves spoken of as genital parts, such as

the heart, whence Aristotle affirms that all the rest of the body is

produced; a statement which we have found borne out by our history. The

heart, I repeat, or at all events its rudimentary parts, namely, the

vesicle and pulsating point, construct the rest of the body as their

future dwelling-place; when erected it enters and conceals itself within

its habitation, which it vivifies and governs, and applying the ribs and

sternum as a defence, it walls itself about. And there it abides, the

household divinity, first seat of the soul, prime receptacle of the

innate heat, perennial centre of animal action; source and origin of all

the faculties; only solace in adversity!

Moreover, since the “efficient” is so styled with reference to the

effect, as some parts produced by epigenesis are posterior in order to

other parts, and are different from antecedent parts,--as effects

differ, so does it seem probable that efficients also vary: from things

that produce different operations, different motions likewise proceed.

Thus physicians in their physiologies assign certain organs as the

agents of chylification, others of sanguification, others of generation,

&c.; and anatomists speak of the ossific, carnific, and neurific

faculties, which they conceive produce bones, flesh, and nerves.

But in the generation of the chick, of several actions differing not a

little from one another, it is certain that the efficient causes must

also differ; those that present themselves to us as accidental

efficients of generation must nevertheless be necessary, seeing, that

unless they are associated or intervene, nothing is effected; those, to

wit, are rightly held “efficients” which, whilst they remove external

hinderances, either cherish the conception, or stimulate and turn mere

potentiality into positive action. Under this head we should arrange

incubation, the proper temperature of the air and the place, the spring

season, the approach of the sun in the circle of the zodiac; in like

manner the preparing causes which lead the vitellus to rise, make the

macula to dilate, and the fluids in the egg to liquefy, are all properly

held “efficients.”

Further, to the number of efficient causes are to be reckoned the

generative and architectonic faculties, styled parts by Fabricius, viz.,

the immutative, the concoctive, the formative, the augmentative, as also

the effective causes of certain accidentals, viz., that which

constitutes the pullet male or female, like the father or the mother,

taking after the form of the first or last male having connection with

the mother; that too whence the offspring is an animal; whether perfect

or defective; robust and healthy, or diseased; longer or shorter lived;

keeping up the characters of the race or degenerating from them; a

monster, an hybrid, &c.

Lastly, when we were discussing the efficient causes of the fœtus, we

were not inattentive to its admirable structure, to the functions and

uses of all its parts and members; neither did we overlook the

foresight, the art, the intelligence, the divine inspiration with which

all things were ordained and skilfully continued for the ends of life.

It is not enough that we inquire what is the “efficient,” the

architect, the adviser, but that we likewise venerate and adore the

omnipotent Creator and preserver of a work, which has been well entitled

a microcosm. We also ask whence this divine something comes, when it

arrives, and where it resides in the egg; this something which is

analogous to the essence of the stars, and is near akin to art and

intelligence, and the vicar of the Almighty Creator?

From what precedes it will be apparent how difficult it were to

enumerate all the efficient causes of the chick; it is indispensable,

indeed, in the complete investigation of this subject to refer to a

general disquisition; we could not from the single generation of the

chick in ovo, and without clearer light derived from investigations

extended to other animals, venture on conclusions that should be

applicable to the whole animal creation. And this all the more, since

Aristotle himself has enumerated such a variety of efficient principles

of animals; for he at one time adduces the ‘male’[254] as the principal

efficient cause, as that, to wit, in which the reason of the engendered

chick resides, according to the axiom;[255] “all things are made by the

same ‘univocal:’” at another time he takes ‘the male semen;’[256] or,

‘the nature of the male emitting semen:’[257] sometimes it is ‘that

which inheres in the semen,’[258] ‘which causes seeds to be prolific,

spirit, to wit, and nature in that spirit corresponding in its qualities

to the essence of the stars:’ elsewhere he says it is ‘heat;’[259]

‘moderate heat;’[260] ‘a certain and proportionate degree of heat;’[261]

‘the heat in the blood;’[262] ‘the heat of the ambient air;’ ‘the

winds;’[263] ‘the sun;’ ‘the heavens;’ ‘Jupiter;’ ‘the soul;’ and,

somewhere, nature is spoken of by him as ‘the principle of motion and

rest.’

Aristotle[264] concludes the discussion on the efficient cause by

declaring it “extremely doubtful” whether it be “anything extrinsic; or

something inherent in the geniture or semen; and whether it be any part

of the soul, or the soul itself, or something having a soul?”

To escape from such a labyrinth of “efficient causes,” it were necessary

to be furnished with Ariadne’s thread, composed from observations on

almost every animal that lives; on this account the subject is deferred

till we come to our more general disquisition. Meantime we shall recount

the particulars which either manifestly appear in the special history of

the chick from the egg, or which differ from the ideas usually

entertained, or that seem to demand further inquiry.

EXERCISE THE FORTY-SEVENTH.

_Of the manner in which the efficient cause of the chick acts, according

to Aristotle._

It is universally allowed, that the male is the primary efficient cause

in generation, on the ground that in him the species or form resides;

and it is further affirmed, that the emission of his ‘geniture’ during

coition, is the cause both of the existence and the fertility of the

egg. But none of the philosophers nor physicians, ancient or modern,

have sufficiently explained in what manner the seed of the cock produced

a chick from the egg; nor have they solved the question proposed by

Aristotle. Nor, indeed, is Aristotle himself much more explanatory, when

he says, “that the male contributes not in respect of quantity, but of

quality, and is the origin of action; but that it is the female which

brings the material.” And a little after, “It is not every male that

emits seed, and in those which do so, this is no part of the fœtus; just

as in the case of a carpenter, nothing is translated from him to the

substance of the wood which he uses, nor does any part of the artist’s

skill reside in the work when completed; but a form and appearance are

given by his operation to the matter; and the soul, which originates the

idea of forms, and the skill to imitate them, moves the hands, or other

limb, whatever it may be, by a motion of a certain quality; or from

diversity proceeds difference; or from similarity proceeds resemblance.

But the hands and instruments move the material. So the nature of a

male, which emits semen, uses that semen as an instrument, and an act

having motion; as in works of art the instruments are moved, for in

them, in some sort, the motion of the art exists.”

By these words he seems to imply, that generation is owing to the motion

of a certain quality. Just as in art, though the first cause (the “ratio

operis”) be in the mind of the artist, yet afterwards, the work is

effected by the movement of the hands or other instruments; and although

the first cause be removed (as in automatons,) yet is it in some sort

said to move what it now does not touch, but once has touched, so long

as motion continues in the instrument.

Also in the next book, he says: “When the semen of the male has arrived

as far as the uterus of the female, it arranges and coagulates the

purest part of the excrement (meaning the menstrual blood existing in

the uterus); and, by a motion of this kind, changes the material, which

has been prepared in the uterus, till it forms part of the chick; and

this, hereafter, although the semen after the performance of this motion

disappears, exists as part of the fœtus, and becomes animate (as the

heart,) and regulates its own powers and growth, as a son emancipated

from his father, and having his own establishment. And so it is

necessary that there be some commencing principle, from which afterwards

the order of the limbs may be delineated, and a proper disposition made

of those things that concern the absolution of the animal; a principle,

which may be the source of growth and motion to all the other parts; the

origin of all, both similar and dissimilar parts, and the source of

their ultimate aliment. For that which is already an animal grows, but

the ultimate aliment of an animal is the blood, or something

corresponding to the blood, whose vessels and receptacles are the veins;

wherefore, the heart is the origin of the veins. But veins, like roots,

spread to the uterus, and through these the fœtus derives its

nourishment. The heart too, being the beginning of all nature and the

containing end, ought to be made first; as if it were a genital part by

its own nature, which, as the original of all the other parts, and of

the whole animal, and of sense, must needs be the first; and by its

heat, (since all the parts are in the material _potentially_,) when once

the beginning of the motion has taken place, all that follows is

excited, just as in spontaneous miracles; and the parts are commenced,

not by change of place, but by alteration in softness, hardness,

temperature, and the other differences observed in similar parts, these

being now actually made, which had before existed only potentially.”

This is, in nearly so many words, the opinion of Aristotle, which

supposes that the fœtus is formed from the seed by motion, although it

is not at present in communication with the fœtus, but simply has been

so at a former time: his reasonings are, indeed, ingenious, and

carefully put together, and from what we see in the order of the

generation of parts, not improbable. For the heart, with the channel of

the veins, is first noticed as an animate principle, in which motion and

sense reside; or, as it were, an emancipated son, and a genital part,

whence the order of the members is delineated, whence all things

pertaining to the completion of the animal are disposed, and which has

all the attributes bestowed upon it by Aristotle.

But it seems impossible, that the heart should be formed in the egg by

the seed of the male, when that seed neither exists in the egg, nor

touches it, nor ever has touched it; because the seed does not enter the

uterus where the egg is, (as is allowed by Fabricius,) nor is in any way

attracted by it; nay, even the maternal blood is not in the egg, nor any

other prepared matter, out of which the seed of the male may form this

genital part, the author of all the others. For it is not immediately

after coition, while the seed still remains within the body, and is in

communication, that any part of the chick exists in the egg, but after

many days, when incubation has taken place. Moreover, in fishes, when

the geniture of the male does nothing but touch the eggs externally, and

does not enter into them, it is not likely that it performs any more

ample functions when the agency is external, than does the seed of the

cock in the already formed eggs of the hen. Besides, since immediately

after coition no trace of the egg as yet exists, but it is afterwards

generated by the hen herself (I am speaking of the prolific egg); when

now the seed of the cock is departed and vanished, there is no

probability that the fœtus is formed in that egg by the aforesaid seed,

through means of one or any number of successive motions.