I, however, suspected the truth of the above views, all the more when I

saw that the words of the philosopher referred to were not accurately

quoted. Aristotle does not say that “Birds which have once copulated

almost all continue to lay prolific eggs,” but simply “almost all

continue to lay eggs;” the word “prolific” is an addition by Fabricius.

But it is one thing to have birds conceiving eggs after intercourse, and

another to say that these eggs are fruitful through this intercourse.

And this is the more obvious from Aristotle’s previous words, where he

says, “Nor in the family of birds can those eggs even that are produced

by intercourse acquire their full size unless the intercourse between

the sexes be continued. And the reason is, that as the menstrual

excretion in women is attracted by the intercourse of their husbands,

(for the uterus, being warmed, draws the moisture, and the passages are

opened,) so in birds it comes to pass that, as the menstruous discharge

takes place very gradually, because of its being in small quantity, it

cannot make its way externally, but is contained superiorly as high as

the waist, and only distils down into the uterus itself. For the egg is

increased by this, just as the fœtus of oviparous animals is nourished

by that which reaches it through the umbilicus. For when once birds have

copulated, almost all continue to lay eggs, but of small size and

imperfect;” and therefore unprolific, for the perfection of an egg is

its being fertile. If, therefore, without continued intercourse, not

even those eggs that were conceived in consequence of intercourse grow

to their proper size, or, as Fabricius interprets it, are “perfected,”

much less are those eggs prolific which fowls continue to lay

independently of intercourse with the male bird.

But lest any one should think that these words, “for the uterus warmed,

draws, and the passages are opened,” signify that the uterus can attract

the semen masculinum into its cavity, let them be aware that the

philosopher does not say that the uterus attracts the semen from without

into its cavity, but that in females, from the veins and passages,

opened by the heat of intercourse, the menstruous blood is attracted

from its own body; so in birds the blood is attracted to the uterus,

warmed by repeated intercourse, whereby the eggs grow, as the fœtus of

oviparous animals grows through the umbilicus.

But what Fabricius adds upon that cavity or bursa, in which he thinks

the semen of the cock may be stored up for a whole year, has been

already refuted by us, where we have stated that it contains no seminal

fluid, and that it exists in the cock as well as in the hen. Wherefore,

though I readily believed (if by fecundity we are to understand a

greater number of larger eggs), that the hens of poor people,

indifferently fed in all probability, will lay both fewer and smaller

eggs unless they have the company of a cock; agreeably to what the

philosopher quoted avers, viz.: “that hens which have once been trodden

continue to lay larger, better, and a greater number of eggs through the

whole of the year,” (a result on which the abundance and the good

quality of the food has unquestionably a great influence); still that

hens should continue for a whole year to lay prolific eggs after a few

addresses of the cock, appeared to me by no means probable: for, had a

small number of contacts sufficed for the purposes of generation during

so long a period, nature, which does nothing in vain, would have

constituted the males among birds less salacious than they are; nor

should we see the cock soliciting his hens so many times a day, even

against their inclination.

We know that the hen, as soon as she quits the nest where she has just

laid an egg, cackles loudly, and seems to entice the cock, who on his

part crowing lustily, singles her out and straightway treads her, which

surely nature had never permitted unless for purposes of procreation.

A male pheasant kept in an aviary was so inflamed with lust, that unless

he had the company of several hen-birds, six at the least, he literally

maltreated them, though his repeated addresses rather interfered with

their breeding than promoted it. I have seen a single hen-pheasant shut

up with a cock-bird (which she could in no way escape) so worn out, and

her back so entirely stript of feathers through his reiterated assaults,

that at length she died exhausted. In the body of this bird, however, I

did not discover even the rudiments of eggs.

I have also observed a male duck, having none of his own kind with him,

but associating with hens, inflamed with such desire that he would

follow a pullet even for several hours, would seize her with his bill,

and mounting at length upon the creature, worn out with fatigue, would

compel her to submit to his pleasure.

The common cock, victorious in a battle, not only satisfies his desires

upon the sultanas of the vanquished, but upon the body of his rival

himself.

The females of some animals are likewise so libidinous that they excite

their males by pecking or biting them gently about the head; they seem

as if they whispered into their ears the sweets of love; and then they

mount upon their backs and invite them by other arts to fruition: among

the number may be mentioned pigeons and sparrows.

It did not therefore appear likely that a few treads, in the beginning

of the year, should suffice to render fertile the whole of the eggs that

are to be laid in its course.

Upon one occasion, however, in the spring season, by way of helping out

Fabricius, and that I might have some certain data as to the time during

which the fecundating influence of intercourse would continue, and the

necessity of renewed communication, I had a couple of hens separated

from the cock for four days, each of which laid three eggs, all of which

were prolific. Another hen was secluded, and the egg she laid on the

tenth day afterwards was fruitful. The egg which another laid on the

twentieth day of her seclusion also produced a chick. It would therefore

seem that intercourse, once or twice repeated, suffices to impregnate

the whole bunch of yelks, the whole of the eggs that will be laid during

a certain season.

I shall here relate another observation which I made at this time. When

I returned two of the hens, which I had secluded for a time, to the

cock, one of which was big with egg, the other having but just laid, the

cock immediately ran to the latter and trod her greedily three or four

times; the former he went round and round, tripping himself with his

wing and seeming to salute her, and wish her joy of her return; but he

soon returned to the other and trod her again and again, even compelling

her to submit; the one big with egg, however, he always speedily

forsook, and never solicited her to his pleasure. I wondered with myself

by what signs he knew that intercourse would advantage one of these hens

and prove unavailing to the other. But indeed it is not easy at any time

to understand how male animals, even from a distance, know which females

are in season and desirous of their company; whether it be by sight, or

hearing, or smell, it is difficult to say. Some on merely hearing the

voice of the female, or smelling at the place where she has made water,

or even the ground over which she has passed, are straightway seized

with desire and set off in pursuit to gratify it. But I shall have more

to say on this subject in my treatise on the Loves, Lusts, and Sexual

Acts of Animals. I return to the matter we have in hand.

EXERCISE THE SEVENTH.

_Of the abdomen of the common fowl and of other birds._

From the external orifice proceeding through the vulva we come to the

uterus of the fowl, in which the egg is perfected, surrounded with the

white and covered with its shell. But before speaking of the situation

and connections of this part it seems necessary to premise a few words

on the particular anatomy of the abdomen of birds. For I have observed

that the stomach, intestines, and other viscera of the feathered kinds

were otherwise placed in the abdomen, and differently constituted, than

they are in quadrupeds.

Almost all birds are provided with a double stomach; one of which is the

crop, the other the stomach, properly so called. In the former the food

is stored and undergoes preparation, in the latter it is dissolved and

converted into chyme.[1] The familiar names of the two stomachs of birds

are the crop or craw, and the gizzard. In the crop the entire grain, &c.

that is swallowed is moistened, macerated, and softened, and then it is

sent on to the stomach that it may there be crushed and comminuted. For

this end almost all the feathered tribes swallow sand, pebbles, and

other hard substances, which they preserve in their stomachs, nothing of

the sort being found in the crop. Now the stomach in birds consists of

two extremely thick and powerful muscles (in the smaller birds they

appear both fleshy and tendinous), so placed that, like a pair of

millstones connected by means of hinges, they may grind and bruise the

food; the place of teeth, which birds want, being supplied by the stones

which they swallow. In this way is the food reduced and turned into

chyme[143]; and then by compression (just as we are wont, after having

bruised an herb or a fruit, to squeeze out the juice or pulp) the softer

or more liquid part is forced out, comes to the top, and is transferred

to the commencement of the intestinal canal; which in birds takes its

rise from the upper part of the stomach near the entrance of the

œsophagus. That this is the case in many genera of birds is obvious; for

the stones and other hard and rough substances which they have

swallowed, if long retained, become so smooth and polished that they are

unfit to comminute the food, when they are discharged. Hence birds, when

they select stones, try them with their tongue, and, unless they find

them rough, reject them. In the stomach of both the ostrich and

cassowary I found pieces of iron and silver, and stones much worn down

and almost reduced to nothing; and this is the reason why the vulgar

believe that these creatures digest iron and are nourished by it.

If you apply the body of a hawk or an eagle, or other bird of prey,

whilst fasting, to your ear, you will hear a distinct noise, occasioned

by the rubbing, one against another, of the stones contained in the

stomach. For hawks do not swallow pebbles with a view to cool their

stomachs, as falconers commonly but erroneously believe, but that the

stones may serve for the comminution of their food; precisely as other

birds, which have muscular stomachs, swallow pebbles, sand, or something

else of the same nature, to crush and grind the seeds upon which they

live.

The stomach of birds, then, is situated within the cavity of the

abdomen, below the heart, lungs and liver: the crop, however, is without

the body in some sort, being situated at the lower part of the neck,

over the os jugale or merry-thought. In this bag, as I have said, the

food is only macerated and softened; and several birds regurgitate and

give it to their young, in some measure as quadrupeds feed their progeny

with milk from their breasts; this occurs in the whole family of the

pigeons, and also among rooks. Bees, too, when they have returned to

their hives, disgorge the honey which they have collected from the

flowers and concocted in their stomachs, and store it in their waxen

cells; and so also do hornets and wasps feed their young. The bitch has

likewise been seen to vomit the food which she had eaten some time

before, in a half-digested state, and give it to her whelps: it is not,

therefore, to be greatly wondered at, if we see the poor women, who beg

from door to door, when their milk fails, feeding their infants with

food which they have chewed and reduced to a pulp in their own mouths.

The intestines commence in birds, as has been said, from the upper part

of the stomach, and are folded up and down in the line of the

longitudinal direction of the body, not transversely as in man.

Immediately below the heart, about the waist, and where the diaphragm is

situated in quadrupeds, for birds have no [muscular] diaphragm, we find

the liver, of ample size, divided into two lobes situated one on either

side (for birds have no spleen,) and filling the hypochondria. The

stomach lies below the liver, and downwards from the stomach comes the

mass of intestines, with numerous delicate membranes, full of air,

interposed; the trachea opening in birds, as already stated, by several

gaping orifices into membranous abdominal cells. The kidneys, which are

of large size in birds, are of an oblong shape, look as if they were

made up of fleshy vesicles, without cavities, and lie along the spine on

either side, with the descending aorta and vena cava abdominalis

adjacent; they further extend into and seem to lie buried within ample

cavities of the ossa ilia. The ureters proceed from the anterior aspects

of the kidneys, and run longitudinally towards the cloaca and podex, in

which they terminate, and into which they pour the liquid excretion of

the kidneys. This, however, is not in any great quantity in birds,

because they drink little, and some of them, the eagle for example, not

at all. Nor is the urine discharged separately and by itself, as in

other animals; but, as we have said, it distils from the ureters into

the common cloaca, which is also the recipient of the fæces, and the

discharge of which it facilitates. The urine is also different in birds

from what it is in other animals; for, as the urine in the generality of

animals consists of two portions, one more serous and liquid, another

thicker, which, in healthy subjects constitutes the hypostasis or

sediment, and subsides when the urine becomes cold; so is it in birds,

but the sedimentary portion is the more abundant, and is distinguished

from the liquid by its white or silvery colour; nor is this sediment met

with only in the cloaca, (where it abounds, indeed, and surrounds the

fæces,) but in the whole course of the ureters, which are distinguished

from the coverings of the kidneys by their white colour. Nor is it only

in birds that this abundant thicker renal secretion is seen; it is

conspicuous in serpents and other ovipara, particularly in those whose

eggs are covered with a harder or firmer membrane. And here, too, is the

thicker in larger proportion than the thinner and more serous portion;

its consistency being midway between thick urine and stercoraceous

excrement: so that, in its passage through the ureters, it resembles

coagulated or inspissated milk; once discharged it soon concretes into a

friable mass.

EXERCISE THE EIGHTH.

_Of the situation and structure of the remaining parts of the fowl’s

uterus._

Between the stomach and the liver, over the spine, and where, in man and

other animals the pancreas is situated; between the trunk of the porta

and the descending cava; at the origin of the renal and spermatic

arteries, and where the cœliac artery plunges into the mesentery, there,

in the fowl and other birds, do the ovary and the cluster of yelks

present themselves; having in their front the trunk of the porta, the

gullet, and the orifice of the stomach: behind them, the vena cava and

the aorta descending along the spine; above the liver, and beneath the

stomach, lie adjacent. The infundibulum, therefore, which is a most

delicate membrane, descends from the ovary longitudinally with the

spine, between it and the gizzard. And from the infundibulum (between

the gizzard, the intestines, the kidneys, and the loins,) the processus

uteri or superior portion of this organ descends with a great many

turnings and cells (like the colon and rectum in man), into the uterus

itself. Now the uterus, which is continuous with this process, is

situated below the gizzard, between the loins, the kidneys, and the

rectum, in the lower part of the abdomen, close to the cloaca; so that

the egg surrounded with its white, which the uterus contains, is

situated so low that, with the fingers, it is easy to ascertain whether

it be soft or hard, and near the laying.

The uterus in the common fowl varies both in point of size and of

structure. In the fowl that is with egg, or that has lately laid, it is

very different from what it is in the pullet, the uterus of which is

fleshy and round, like an empty purse, and its cavity so insignificant

that it would scarcely contain a bean; smooth externally, it is wrinkled

and occupied by a few longitudinal plicæ internally: at first sight you

might very well mistake it either for a large urinary bladder or for a

second smaller stomach. In the gravid state, however, and in the fowl

arrived at maturity (a fact which is indicated by the redder colour of

the comb), the uterus is of much larger dimensions and far more fleshy;

its plicæ are also larger and thicker, it in general approaches the size

which we should judge necessary to receive an egg; it extends far

upwards in the direction of the spinal column, and consists of numerous

divisions or cells, formed by replications of the extended uterus,

similar to those of the colon in quadrupeds and man. The inferior

portion of the uterus, as the largest and thickest, and most fleshy of

all, is strengthened by many plicæ of large size. Its configuration

internally is oval, as if it were the mould of the egg. The ascending or

produced portion of the uterus I designate the processus uteri: this

part Fabricius calls the “uterus secundus,” and says that it consists of

three spiral turns or flexures; Ulyssus Aldrovandus, again, names it the

“stomachum uteri.” I must admit that in this part there are usually

three turns to be observed; they are not, however, by any means so

regular but that, as in the case of the cells of the colon, nature

sometimes departs from her usual procedure here.

The uterus as it ascends higher, so does it become ever the thinner and

more delicate, containing fewer and smaller plicæ, until at length going

off into a mere membrane, and that of the most flimsy description, it

constitutes the infundibulum; which, reaching as high as the waist or

cincture of the body, embraces the entire ovary.

On this account, therefore, Fabricius describes the uterus as consisting

of three portions; viz., the commencement, the middle, and the end. “The

commencement,” says he, “degenerating into a thin and most delicate

membrane, forms an ample orifice, and bears a resemblance to an

open-mouthed tube or funnel. The next portion (which I call the

processus uteri), consisting of three transverse spiral turns, serves

for the supply of the albumen, and extends downwards to the most

inferior and capacious portion--the termination of the uterus--in which

the chalazæ, the two membranes, and the shell are formed.[144]”

The whole substance of the uterus, particularly the parts about the

plicæ, both in its body and in its process, are covered with numerous

ramifications of blood-vessels, the majority of which are arterial

rather than venous branches.

The folds which appear oblique and transverse in the interior of the

uterus are fleshy substances; they have a fine white or milky colour,

and a sluggish fluid oozes from them, so that the whole of the interior

of the uterus, as well the body as the process, is moistened with an

abundance of thin albumen, whereby the vitellus as it descends is

increased, and the albumen that is deposited around it is gradually

perfected.

The uterus of the fowl is rarely found otherwise than containing an egg,

either sticking in the spiral process or arrived in the body of the

organ. If you inflate this process when it is empty it then presents

itself as an oblique and contorted tube, and rises like a turbinated

shell or cone into a point. The general arrangement of the spirals and

folds composing the uterus, is such as we have already observed it in

the vulva: there is a ready enough passage for the descending egg, but

scarce any return even for air blown in towards the superior parts.

The processus uteri with its spirals, very small in the young pullet, is

so much diminished in the hen which has ceased laying, that it shrinks

into the most delicate description of membrane, and then entirely

disappears, so that no trace of it remains, any more than of the ovary

or infundibulum: nothing but a certain glandular-looking and spongy mass

appears in the place these bodies occupied, which in a boiled fowl

tastes sweet, and bears some affinity to the pancreas and thymus of

young mammiferous animals, which, in the vernacular tongue, are called

the sweetbread.

The uterus and the processus uteri are connected with the back by means

of a membranous attachment, which Fabricius designates by the name of

“mesometrium; because the second uterus, together with this vascular and

membranous body, may very fairly be compared with the intestines and

the mesentery.” For, as the intestine is bound down by the mesentery, so

is this portion of the uterus attached to the spinal column by an oblong

membranous process; lest by being too loose, and getting twisted, the

passage of the yelks should be interfered with, instead of having a free

and open transit afforded them as at present. The mesometrium also

transmits numerous blood-vessels surcharged with blood, to each of the

folds of the uterus. In its origin, substance, structure, use, and

office, this part is therefore analogous to the mesentery. Moreover,

from the fundus of the uterus lengthwise, and extending even to the

infundibulum, there is a ligament bearing some resemblance to a

tape-worm, similar to that which we notice in the upper part of the

colon. It is as if a certain portion or stripe of the external tunic had

been condensed and shortened in such a manner that the rest of the

process is thrown into folds and cells: were you to draw a thread

through a piece of intestine taken out of the body, and to tie this

thread firmly on one side, you would cause the other side of the bowel

to pucker up into wrinkles and cells; [even so is it with the uterus of

the fowl.]

This then, in brief, is the structure of the uterus in the fowl that is

laying eggs: fleshy, large, extensible both longitudinally and

transversely, tortuous or winding in spirals and convolutions from the

cloaca upwards, in the line of the vertebral column, and continued into

the infundibulum.

EXERCISE THE NINTH.

_Of the extrusion of the egg, or parturition of the fowl, in general._

The yelk, although only a minute speck in the ovary, gaining by degrees

in depth of colour and increasing in size, gradually acquires the

dimensions and characters that distinguish it at last. Cast loose from

the cluster, it descends by the infundibulum, and, transmitted through

the spirals and cells of the processus uteri, it becomes surrounded with

albumen; and this, without in any place adhering to the uterus (as was

rightly observed by Fabricius in opposition to Aristotle), or growing by

means of any system of umbilical vessels; but as the eggs of fishes and

frogs, when extruded and laid in the water provide and surround

themselves with albumen, or as beans, vetches, and other seeds and

grains swell when moistened, and thence supply nourishment to the germs

that spring from them, so, from the folds of the uterus that have been

described, as from an udder, or uterine placenta, an albuminous fluid

exudes, which the vitellus, in virtue of its inherent vegetative heat

and faculty, attracts and digests into the surrounding white. There is,

indeed, an abundance of fluid having the taste of albumen, contained in

the cavity of the uterus and entangled between the folds that cover its

interior. In this way does the yelk, descending by degrees, become

surrounded with albumen, until at last, having in the extreme part of

the uterus acquired a covering of firmer membranes and a harder shell,

it is perfected and rendered fit for extrusion.

EXERCISE THE TENTH.

_Of the increase and nutrition of the egg._

Let us hear Fabricius on these topics. He says: “As the action of the

stomach is to prepare the chyle, and that of the testes to secrete the

seminal fluid, (because in the stomach chyle is discovered, and in the

testes semen,) so we declare the act of the uterus in birds to be the

production of eggs, because eggs are found there. But this, as it

appears, is not the only action of uteri; to it must be added the

increase of the egg, which succeeds immediately upon its production, and

which proceeds until it is perfected and attains its due size. For a

fowl does not naturally lay an egg until it is perfect and has attained

to its proper dimensions. The office of the uterus is, therefore, the

growth as well as the generation of the egg; but growth implies and

includes the idea of nutrition; and, as all generation is the act of two

principles, one the agent, another the matter, the agent in the

production of eggs is nothing else than the organs or instruments

indicated, viz., the compound uterus; and the matter nothing but the

blood.”

We, studious of brevity, and shunning all controversy, as in duty

bound, as we readily admit that the office and use of the uterus is the

procreation of the egg, so do we maintain the “adequate efficient,” as

it has been called, the immediate agent to inhere in the egg itself; and

we assert farther, that the egg is both engendered and made to increase,

not by the uterus, but by a certain natural principle peculiar to

itself; and that this principle flows from the whole fowl into the

rudiments of the vitellus, and whilst it was yet but a speck, and under

the influence either of the calidum innatum or of nature, causes it to

be nourished and to grow; just as there is a certain faculty in every

particle of the body which secures its nutrition and growth.

As regards the manner in which the yelk is surrounded by the albumen,

Aristotle appears to have believed[145] that in the sharp end of the egg

(where he placed the commencement of the egg), whilst it was yet

surrounded by soft membranes, there existed an umbilical canal, by which

it was nourished; a view which Fabricius[146] challenges, denying that

there is any such canal, or that the vitellus has any kind of connexion

with the uterus. He farther lessens the doubt in regard to the albumen

of the extruded egg, observing, that “the egg increases in a two-fold

manner, inasmuch as the uterus consists of two portions, one superior,

another inferior; and the egg itself consists of two matters--the yelk

and the white. The yelk increases with a true growth, to wit, by means

of the blood, which is sent to it through the veins whilst it is yet

connected with the vitellarium. The albumen, however, increases and

grows otherwise than the yelk; viz., not by means of the veins, nor by

proper nutrition like the yelk, but, by juxtaposition, adhering to the

vitellus as it is passing through the second uterus.”

But my opinion is, that the egg increases everywhere in the same manner

as the yelk does in the cluster; viz. by an inherent concocting

principle; with this single difference, that in the ovary the

nourishment is brought to it by means of vessels, whilst in the uterus

it finds that which it imbibes already prepared for it. Juxtaposition of

parts is equally necessary in every kind of nutrition and growth, and so

also are concoction and distribution of the applied nutriment. Nor is

one of these to be less accounted true nutrition than the other,

inasmuch as in both there is accession of new aliment, apposition,

agglutination, and transmutation of particles. Nor can vetches or beans,

when they attract moisture from the earth through their skins, imbibing

it like sponges, be said with less propriety to be nourished than if

they had obtained the needful moisture through the mouths of veins; and

trees, when they absorb the dew and the rain through their bark, are as

truly nourished as when they pump them in by their roots. With reference

to the mode in which nutrition is effected, we have set down much in

another place. It is another difficulty that occupies us at this time,

viz., whether the yelk, whilst it is acquiring the white, does not make

a certain separation and distinction in it; whether, in the course of

the increase, a more earthy portion does not subside into the yelk or

middle of the egg as towards the centre, which Aristotle believed, and

another lighter portion surrounds this. For between the yelk which is

still in the cluster, and the yelk which is found in the middle of a

perfect egg, there is this principal difference, that although the

former be of a yellow colour, still, in point of consistence, it rather

resembles the white; and by boiling, it is, like the latter, thickened,

compacted, inspissated, and becomes divisible into layers; whilst the

yelk of the perfect egg is rendered friable by boiling, and is rather of

an earthy consistency, not thick and gelatinous like albumen.

EXERCISE THE ELEVENTH.

_Of the covering or shell of the egg._

It will now be proper, having spoken of the production of eggs, to treat

of their parts and diversities. “An egg,” says Fabricius, “consists of a

yelk, the albumen, two chalazæ, three membranes, viz. one proper to the

vitellus, two common to the entire egg, and a shell. To these two others

are to be added, which, however, cannot be correctly reckoned among the

parts of an egg; one of these is a small cavity in the blunt end of the

egg, under the shell; the other is a very small white spot, a kind of

round cicatricula connected with the surface of the yelk. The history of

each of these parts and accidents must now be given more particularly,

and we shall begin from without and proceed inwards.

“The external covering of the egg, called by Pliny the cortex and

putamen, by Quintus Serenus the testa ovi, is a hard but thin, friable

and porous covering, of different colours in different cases--white,

light green, speckled, &c. All eggs are not furnished with a shell on

their extrusion: the eggs of serpents have none; and some fowls

occasionally, though rarely, lay eggs that are without shells. The

shell, though everywhere hard, is not of uniform hardness; it is hardest

towards the upper end.” From this Fabricius[147] opines that we are to

doubt as to the matter of which, and the season at which the shells of

eggs are produced. Aristotle[148] and Pliny[149] affirm that the shell

is not formed within the body of the fowl, but when the egg is laid; and

that as it issues it sets by coming in contact with the air, the

internal heat driving off moisture. And this, says Aristotle,[150] is so

arranged to spare the animal pain, and to render the process of

parturition more easy. An egg softened in vinegar is said to be easily

pushed into a vessel with a narrow mouth.

Fabricius was long indisposed to this opinion, “because he had found an

egg within the body of the fowl covered with a hard shell; and

housewives are in the daily practice of trying the bellies of their hens

with their fingers in order that they may know by the hardness whether

the creatures are likely to lay that day or not.” But by-and-by, when

“he had been assured by women worthy of confidence, that the shells of

eggs became hardened in their passage into the air, which dissipates a

certain moisture diffused over the egg on its exit, fixing it in the

shell not yet completely hardened;” and having afterwards “confirmed

this by his own experience,” he altered his opinion, and came to the

conclusion, “that the egg surrounded with a shell, and having a

consistency betwixt hard and soft, hardened notably at the moment of its

extrusion, in consequence, according to Aristotle’s views, of the

concretion and dissipation of the thinner part of a certain viscid and

tenacious humour, bedewed with which the egg is extruded; sticking to

the recent shell this humour is dried up and hardened, the cold of the

ambient air contributing somewhat to the effect. Of all this,” he says,

“you will readily be satisfied if you have a fowl in the house, and

dexterously catch the egg in your hand as it is dropping.”

I was myself long fettered by this statement of Aristotle, indeed until

certain experience had assured me of its erroneousness; for I found the

egg still contained in the uterus, almost always covered with a hard

shell; and I once saw an egg taken from the body of a living fowl, and

still warm, without a shell but covered with a tenacious moisture; this

egg, however, did not acquire any hardness through the concretion or

evaporation of the moisture in question, as Fabricius would have us

believe, neither was it in any way changed by the cold of the

surrounding air; but it retained the same degree of softness which it

had had in the uterus.

I have also seen an egg just laid by a fowl, surrounded by a complete

shell, and this shell covered externally with a soft and membranous

skin, which however did not become hard. I have farther seen another

hen’s egg covered with a shell everywhere except at the extremity of the

sharp end, where a certain small and soft projection remained, very

likely such as was taken by Aristotle for the remains of an umbilicus.

Fabricius, therefore, appears to me to have wandered from the truth; nor

was I ever so dexterous as to catch an egg in its exit, and discover it

in the state between soft and hard. And this I confidently assert, that

the shell is formed internally, or in the uterus, and not otherwise than

all the other parts of the egg, viz. by the peculiar plastic power. A

statement which I make all the more confidently because I have seen a

very small egg covered with a shell, contained within another larger

egg, perfect in all respects, and completely surrounded with a shell. An

egg of this kind Fabricius calls an ovum centeninum; and our housewives

ascribe it to the cock. This egg I showed to his serene Majesty King

Charles, my most gracious master, in the presence of many persons. And

the same year, in cutting up a large lemon, I found another perfect but

very small lemon included within it, having a yellow rind like the

other; and I hear that the same thing has frequently been seen in Italy.

It is a common mistake with those who pursue philosophical studies in

these times, to seek for the cause of diversity of parts in diversity

of the matter whence they arise. Thus medical men assert that the

several parts of the body are both engendered and nourished by diverse

matters, either the blood or the seminal fluid; viz. the softer parts,

such as the flesh, by the thinner matter, the harder and more earthy

parts, such as the bones, &c. by the firmer and thicker matter. But we

have elsewhere refuted this too prevalent error. Nor do they err less

who, with Democritus, compose all things of atoms; or with Empedocles,

of elements. As if _generation_ were nothing more than a separation, or

aggregation, or disposition of things. It is not indeed to be denied,

that when one thing is to be produced from another, all these are

necessary, but generation itself is different from them all. I find

Aristotle to be of this opinion; and it is my intention, by-and-by, to

teach that out of the same albumen (which all allow to be uniform, not

composed of diverse parts,) all the parts of the chick, bones, nails,

feathers, flesh, &c. are produced and nourished. Moreover, they who

philosophize in this way, assign a material cause [for generation], and

deduce the causes of natural things either from the elements concurring

spontaneously or accidentally, or from atoms variously arranged; they do

not attain to that which is first in the operations of nature and in the

generation and nutrition of animals; viz. they do not recognize that

efficient cause and divinity of nature which works at all times with

consummate art, and providence, and wisdom, and ever for a certain

purpose, and to some good end; they derogate from the honour of the

Divine Architect, who has not contrived the shell for the defence of the

egg with less of skill and of foresight than he has composed all the

other parts of the egg of the same matter, and produced it under the

influence of the same formative faculty.

Although what has already been said be the fact, namely, that the egg,

even whilst contained in the uterus, is provided with a hard shell,

still the authority of Aristotle has always such weight with me that I

never think of differing from him inconsiderately; and I therefore

believe, and my observations bear me out in so much, that the shell does

gain somewhat in solidity from the ambient air upon its extrusion; that

the sluggish and slippery fluid with which it is moistened when laid,

immediately becomes hardened on its exposure to the air. For the shell,

whilst the egg is in the uterus, is much thinner and more transparent,

and smoother on the surface; when laid, however, the shell is thicker,

less translucid, and the surface is rough--it appears as if it were

powdered over with a fine white dust which had but just adhered to it.

Let us, as we are upon this subject, expatiate a little:--

In the desert islands of the east coast of Scotland, such flights of

almost every kind of sea-fowl congregate, that were I to state what I

have heard from parties very worthy of credit, I fear I should be held

guilty of telling greater stories than they who have committed

themselves in regard to the Scottish geese produced, as they say, from

the fruits of certain trees that had fallen into the sea. These geese

the narrators themselves had never seen so produced; but I will here

relate that which I have myself witnessed.

There is a small island which the Scots call the Bass Island (and

speaking of this one will suffice for all), situated in the open ocean,

not far from the shore, of the most abrupt and precipitous character, so

that it rather resembles one huge rock or stone than an island, and

indeed it is not more than a mile in circumference. The surface of this

island in the months of May and June is almost completely covered with

nests, eggs, and young birds, so that you can scarce find free footing

anywhere; and then such is the density of the flight of the old birds

above, that like a cloud they darken the sun and the sky; and such the

screaming and din that you can scarce hear the voice of one who

addresses you. If you turn your eyes below, and from your lofty stance

and precipice regard the sea, there you perceive on all sides around an

infinite variety of different kinds of sea-fowl swimming about in

pursuit of their prey: the face of the ocean is very like that of a pool

in the spring season, when it appears swarming with frogs; or to those

sunny hills and cliffy mountains looked at from below, that are covered

with numerous flocks of sheep and goats. If you sail round the island

and look up, you see on every ledge and shelf, and recess, innumerable

flocks of birds of almost every size and order; more numerous than the

stars that appear in the unclouded moonless sky; and if you regard the

flights that incessantly come and go you may imagine that it is a mighty

swarm of bees you have before you. I should scarcely be credited did I

name the revenue which was annually derived from the feathers, the eggs,

and the old nests, which, as useful for firing, are all made objects of

traffic by the proprietor; the sum he mentioned to me exceeds

credibility. There was this particular feature which, as it refers to

our subject, I shall mention, and also as it bears me out in my report

of the multitudes of sea-fowl: the whole island appears of a brilliant

white colour to those who approach it,--all the cliffs look as if they

consisted of the whitest chalk; the true colour of the rock, however, is

dusky and black. It is a friable white crust that is spread over all,

which gives the island its whiteness and splendour, a crust, having the

same consistency, colour, and nature as an egg-shell, which plasters

everything with a hard, though friable and testaceous kind of covering.

The lower part of the rock, laved by the ebbing and flowing tide,

preserves its native colour, and clearly shows that the whiteness of the

superior parts is due to the liquid excrements of the birds, which are

voided along with the alvine fæces; which liquid excrements, white,

hard, and brittle like the shell of the egg, cover the rock, and, under

the influence of the cold of the air, incrust it. Now this is precisely

the way in which Aristotle and Pliny will have it that the shell of the

egg is formed. None of the birds are permanent occupants of the island,

but visitors for purposes of procreation only, staying there for a few

weeks, in lodgings, as it were, and until their young ones can take wing

along with them. The white crust is so hard and solid, and adheres so

intimately to the rock, that it might readily be mistaken for the

natural soil of the place.

The liquid, white, and shining excrement is conveyed from the kidneys of

birds by the ureters, into the common receptacle or cloaca; where it

covers over the alvine fæces, and with them is discharged. It

constitutes, in fact, the thicker portion of the urine of these

creatures, and corresponds with that which, in our urine, we call the

hypostase or sediment. We have already said something above on this

topic, and have entered into it still more fully elsewhere. We always

find an abundance of this white excrement in mews; where hawks besmear

walls beside their perches, they cover them with a kind of gypseous

crust, or make them look as if they were painted with white lead.

In the cloaca of a dead ostrich I found as much of this gypseous cement

as would have filled the hand. And in like manner the same substance

abounds in tortoises and other oviparous animals; discharged from the

body it soon concretes either into a friable crust, or into a powder

which greatly resembles pulverized egg-shells, in consequence of the

evaporation of its thinner part.

Among the many different kinds of birds which seek the Bass island for

the sake of laying and incubating their eggs, and which have such

variety of nests, one bird was pointed out to me which lays but one egg,

and this it places upon the point of a rock, with nothing like a nest or

bed beneath it, yet so firmly that the mother can go and return without

injury to it; but if any one move it from its place, by no art can it be

fixed or balanced again; left at liberty, it straightway rolls off and

falls into the sea. The place, as I have said, is crusted over with a

white cement, and the egg, when laid, is bedewed with a thick and viscid

moisture, which setting speedily, the egg is soldered as it were, or

agglutinated to the subjacent rock.

An instance of like rapid concretion may be seen any day at a

statuary’s, when he uses his cement of burnt alabaster or gypsum

tempered with water; by means of which the likeness of one dead, or the

cast of anything else may be speedily taken, and used as a mould.

There is also in like manner a certain earthy or solid something in

almost all liquids, as, for example, tartar in wine, mud or sand in

water, salt in lixivium, which, when the greater portion of the water

has been dissipated, concretes and subsides; and so do I conceive the

white sediment of birds to descend along with the urine from the kidneys

into the cloaca, and there to cover over and incrust the egg, much as

the pavement of a mews is plastered over by falcons, and every cliff of

the aforementioned island by the birds that frequent it; much also as

chamber utensils, and places where many persons make water, become

covered with a yellow incrustation; that substance, in fact, concreting

externally, of which calculi in the kidneys, bladder, and other parts

are formed. I did formerly believe then, as I have said, persuaded

especially by the authority of Aristotle and Pliny, that the shell of

the hen’s egg was formed of this white sediment, which abounds in all

the oviparous animals whose eggs are laid with a hard shell, the matter

concreting through contact with the air when the egg was laid. And so

many additional observations have since strengthened this conclusion,

that I can scarcely keep from believing that some part at least of the

shell is thus produced.

Nevertheless, I would say with Fabricius: “Let all reasoning be silent

when experience gainsays its conclusions.” The too familiar vice of the

present age is to obtrude as manifest truths, mere fancies, born of

conjecture and superficial reasoning, altogether unsupported by the

testimony of sense.

For I have very certainly discovered that the egg still contained in the

uterus, in these countries at least, is covered with its shell; although

Aristotle and Pliny assert the contrary, and Fabricius thinks that “it

is not to be too obstinately gainsaid.” In warmer places, perhaps, and

where the fowls are stronger, the eggs may be extruded soft, and for the

most part without shells. With us this very rarely happens. When I was

at Venice in former years, Aromatarius, a learned physician, showed me a

small leaf which had grown between the two valves of a peascod, whilst

with us there is nothing more apparent in these pods than a small point

where the germ is about to be produced. So much do a milder climate, a

brighter sky, and a softer air, conduce to increase and rapidity of

growth.

EXERCISE THE TWELFTH.

_Of the remaining parts of the egg._

We have already spoken partially of the place where, the time when, and

the manner how the remaining parts of the egg are engendered, and we

shall have something more to add when we come to speak of their several

uses.

“The albumen,” says Fabricius,[151] “is the _ovi albus liquor_ of Pliny,

the _ovi candidum_ of Celsus, the _ovi albor_ of Palladius, the _ovi

album et albumentum_ of Apicius, the λευκὸν of the Greeks, the ώοῡ

λεύκωμα of Aristotle, the ὄρνιθος γάλα, or bird’s milk of Anaxagoras.

This is the cold, sluggish, white fluid of the egg, of different

thickness at different places (thinner at the blunt and sharp ends,

thicker in other situations,) and also in variable quantity (for it is

more abundant at the blunt end, less so at the sharp end, and still less

so in the other parts of the egg), covering and surrounding the yelk on

every side.”

In the hen’s egg, however, I have observed that there are not only

differences in the albumen, but two albumens, each surrounded with its

proper membrane. One of these is thinner, more liquid, and almost of the

same consistence as that humour which, remaining among the folds of the

uterus, we have called the matter and nourishment of the albumen; the

other is thicker, more viscid, and rather whiter in its colour, and in

old and stale eggs, and those that have been sat upon for some days, it

is of a yellowish cast. As this second albumen everywhere surrounds the

yelk, so is it, in like manner, itself surrounded by the more external

fluid. That these two albumens are distinct appears from this, that if

after having removed the shell you pierce the two outermost membranes,

you will perceive the external albuminous liquid to make its escape, and

the membranes to become collapsed and to sink down in the dish; the

internal and thicker albumen, however, all the while retains its place

and globular figure, inasmuch as it is bounded by its proper membrane,

although this is of such tenuity that it entirely escapes detection by

the eye; but if you then prick it, the second albumen will forthwith

begin to flow out, and the mass will lose its globular shape; just as

the water contained in a bladder escapes when it is punctured; in like

manner the proper investing membrane of the vitellus being punctured,

the yellow fluid of which it consists escapes, and the original globular

form is destroyed.

“The vitellus,” says Fabricius,[152] “is so called from the word vita,

because the chick lives upon it; from its colour it is also spoken of as

the yellow of the egg, having been called by the Greeks generally,

χρυσὸν, by Hippocrates χλωρὸν, and by Aristotle ώχρὸν and λεκυθὸν; the

ancients, such as Suidas in Menander, called it νεοττὸν, i. e. the

chick, because they believed the chick to be engendered from this part.

It is the smoothest portion of the egg, and is contained within a most

delicate membrane, immediately escaping if this be torn, and losing all

figure; it is sustained in the middle of the egg; and in one egg is of

a yellow colour, in another of a tint between white and yellow; it is

quite round, of variable size, according to the size of the bird that

lays the egg, and, according to Aristotle, of a deeper yellow in water

birds, of a paler hue in land birds.” The same author[153] also

maintains that “the yellow and the white of an egg are of opposite

natures, not only in colour but in qualities; for the yellow is

inspissated by cold, which the white is not, but is rather rendered more

liquid; and the white, on the contrary, is thickened by heat, which the

yellow is not, unless it be burned or over-done, and it is more hardened

and dried by boiling than by roasting.” As in the macrocosm the earth is

placed in the centre, and is surrounded by the water and the air, so is

the yelk, the more earthy part of the egg, surrounded by two albuminous

layers, one thicker, another thinner. And, indeed, Aristotle[154] says

that, “if we put a number of yelks and whites together, and mix them in

a pan, and then boil them with a slow and gentle fire, that the whole of

the yelks will set into a globular mass in the middle, and appear

surrounded by the whites.” But many physicians have been of opinion that

the white was the colder portion of the egg. Of these matters, however,

more by and by.

The chalazæ, the treads or treadles (gralladura Ital.) are two in number

in each egg, one in the blunt, another in the sharp end. The larger

portion of them is contained in the white; but they are most intimately

connected with the yelk, and with its membrane. They are two long-shaped

bodies, firmer than the albumen and whiter; knotty, not without a

certain transparency like hail, whence their name; each chalaza, in

fact, is made up of several hailstones, as it seems, connected by means

of albumen. One of them is larger than the other, and this extends from

the yelk towards the blunt end of the egg; the other and smaller chalaza

stretches from the yelk towards the sharp end of the egg. The larger is

made up of two or three knots or seeming hailstones, at a trifling

distance from one another, and of successively smaller size.

The chalazæ are found in the eggs of all birds, and in wind and

unprolific as well as in perfect or prolific eggs, duly disposed in both

their extremities. Whence the supposition among housewives that the

chalazæ are the tread or spermatic fluid of the cock, and that the chick

is generated from them is discovered to be a vulgar error. But Fabricius

himself, although he denies that they consist of the semen of the cock,

still gives various reasons for maintaining that “they are the immediate

matter which the cock fecundates, and from which the chick is produced;”

a notion which he seeks to prop by this feeble statement: “because in a

boiled egg, the chalazæ are so contracted on themselves that they

present the figure of a chick already formed and hatched.” But it is not

likely that several rudiments of a single fœtus should be wanted in one

egg, neither has any one ever discovered the rudiments of the future

chick save in the blunt end of the egg. Moreover the chalazæ present no

sensible difference in eggs that are fecundated by the intercourse of

the two sexes, from those of eggs that are barren. Our distinguished

author is therefore mistaken in regard to the use of the chalazæ in the

egg, as shall farther be made to appear by and by.

In the eggs of even the smallest birds there is a slender filament, the

rudiments of the chalazæ, to be discovered; and in those of the ostrich

and cassowary I have found, in either end of the egg very thick chalazæ,

of great length, and very white colour, made up of several globules

gradually diminishing in size.

A small cavity is observed in the inside of an egg under the shell, at

the blunt end; sometimes exactly in the middle, at other times more to

one side, almost exactly corresponding to the chalaza that lies below

it. The figure of this cavity is generally circular, though in the goose

and duck it is not exactly so. It is seen as a dark spot if you hold an

egg opposite a candle in a dark place, and apply your hand edgeways over

the blunt end. In the egg just laid it is of small size,--about the size

of the pupil of the human eye; but it grows larger daily as the egg is

older, and the air is warmer; it is much increased after the first day

of incubation; as if by the exhalation of some of the more external and

liquid albumen the remainder contracted, and left a larger cavity; for

the cavity in question is produced between the shell and the membrane

which surrounds the whole of the fluids of the egg. It is met with in

all eggs; I have discovered it, even in those that are still contained

in the uterus, as soon as they had become invested with the shell. They

who are curious in such matters say that if this cavity be in the point

or end of the egg it will produce a male, if towards the side, a female.

This much is certain: if the cavity be small it indicates that the egg

is fresh-laid; if large, that it is stale. But we shall have occasion

anon to say more on this head.

There is a white and very small circle apparent in the investing

membrane of the vitellus, which looks like an inbranded cicatrice, which

Fabricius therefore calls cicatricula; but he makes little of this spot,

and looks on it rather as an accident or blemish than as any essential

part of the egg. The cicatricula in question is extremely small; not

larger than a tiny lentil, or the pupil of a small bird’s eye; white,

flat, and circular. This part is also found in every egg, and even from

its commencement in the vitellarium. Fabricius, therefore, is mistaken

when he thinks that this spot is nothing more than the trace or

cicatrice of the severed peduncle, by which the egg was in the first

instance connected with the ovary. For the peduncle, as he himself

admits, is hollow, and as it approaches the vitellus expands, so as to

surround or embrace, and inclose the yelk in a kind of pouch: it is not

connected with the yelk in the same way as the stalks of apples and

other fruits are infixed, and so as to leave any cicatrice when the yelk

is cast loose. And if you sometimes find two cicatriculæ in a large

yelk, as Fabricius states, this might, perhaps, lead to the production

of a monster and double fœtus, (as shall be afterwards shown), but would

be no indication of the preexistence of a double peduncle. He is,

however, immensely mistaken when he imagines that the cicatricula serves

no purpose; for it is, in fact, the most important part of the whole

egg, and that for whose sake all the others exist; it is that, in a

word, from which the chick takes its rise. Parisanus, too, is in error,

when he contends that this is the semen of the cock.

EXERCISE THE THIRTEENTH.

_Of the diversities of eggs._

“The word ovum, or egg, is taken in a twofold sense, proper and

improper. An ovum, properly so designated, I call that body to which the

definition given by Aristotle[155] applies: An egg, says he, is that

from part of which an animal is engendered, and the remainder of which

is food for the animal so produced. But I hold that body to be

improperly styled an egg which is defined by Aristotle[156] in the same

place, to be that from the whole of which an animal is engendered; such

as the eggs of ants, flies, spiders, some butterflies, and others of the

tribe of extremely small eggs; which Aristotle almost always fears to

commit himself by calling eggs, but which he rather styles vermiculi.”

What precedes is from Fabricius;[157] but we, whose purpose it is to

treat especially of the generation of the hen’s egg, have no intention

to speak of the differences of all kinds of eggs; we shall limit

ourselves to the diversities among hen’s eggs.

The more recently laid are whiter than the staler, because by age, and

especially by incubation, they become darker; the cavity in the blunt

end of a stale egg is also larger than in a recent egg; eggs just laid

are also somewhat rough to the feel from a quantity of white powder

which covers the shell, but which is soon rubbed off, when the egg

becomes smoother as well as darker. New-laid eggs, unbroken, if placed

near a fire will sweat, and are much more palatable than those that have

been kept for some time--they are, indeed, accounted a delicacy by some.

[Fruitful] eggs, after two or three days’ incubation, are still better

flavoured than stale eggs; revived by the gentle warmth of the hen, they

seem to return to the quality and entireness of the egg just laid.

Farther, I have boiled an egg to hardness, after the fourteenth day of

incubation, when the chick had already begun to get its feathers, when

it occupied the middle of the egg, and nearly the whole of the yelk

remained, in order that I might better distinguish the position of the

chick: I found it lying, as it were, within a mould of the albumen, and

the yelk possessed the same agreeable flavour and sweetness as that of

the new-laid egg, boiled to the same degree of hardness. The yelk taken

from the ovarium of a live fowl, and eaten immediately, tastes much

sweeter raw than boiled.

Eggs also differ from one another in shape; some are longer and more

pointed, others rounder and blunter. According to Aristotle,[158] the

long-shaped and pointed eggs produce females; the blunt, on the

contrary, yield males. Pliny,[159] however, maintains the opposite. “The

rounder eggs,” he says, “produce females, the others males;” and with

him Columella[160] agrees: “He who desires to have the greater number of

his brood cocks, let him select the longest and sharpest eggs for

incubation; and on the contrary, when he would have the greater number

females, let him choose the roundest eggs.” The ground of Aristotle’s

opinion was this: because the rounder eggs are the hotter, and it is the

property of heat to concentrate and determine, and that heat can do most

which is most powerful. From the stronger and more perfect principle,

therefore, proceeds the stronger and more perfect animal. Such is the

male compared with the female, especially in the case of the common

fowl. On the contrary, again, the smaller eggs are reckoned among the

imperfect ones, and the smallest of all are regarded as entirely

unproductive. It was on this account too that Aristotle, to secure the

highest quality of eggs, recommends that the hens be frequently trodden.

Barren and adventitious eggs, he asserts, are smaller and less savoury,

because they are humid and imperfect. The differences indicated are to

be understood as referring to the eggs of the same fowl; for when a

certain hen goes on laying eggs of a certain character, they will all

produce either males or females. If you understand this point otherwise,

the guess as to males or females, from the indications given, would be

extremely uncertain. Because different hens lay eggs that differ much in

respect of size and figure: some habitually lay more oblong, others,

rounder eggs, that do not differ greatly one from another; and although

I sometimes found diversities in the eggs of the same fowl, these were

still so trifling in amount that they would have escaped any other than

the practised eye. For as all the eggs of the same fowl acquire nearly

the same figure, in the same womb or mould in which the shell is

deposited, (much as the excrements are moulded into scybala in the cells

of the colon,) it necessarily falls out that they greatly resemble one

another; so that I myself, without much experience, could readily tell

which hen in a small flock had laid a given egg, and they who have given

much attention to the point, of course succeed much better. But that

which we note every day among huntsmen is far more remarkable; for the

more careful keepers who have large herds of stags or fallow deer under

their charge, will very certainly tell to which herd the horns which

they find in the woods or thickets belonged. A stupid and uneducated

shepherd, having the charge of a numerous flock of sheep, has been known

to become so familiar with the physiognomy of each, that if any one had

strayed from the flock, though he could not count them, he could still

say which one it was, give the particulars as to where it had been

bought, or whence it had come. The master of this man, for the sake of

trying him, once selected a particular lamb from among forty others in

the same pen, and desired him to carry it to the ewe which was its dam,

which he did forthwith. We have known huntsmen who, having only once

seen a particular stag, or his horns, or even his print in the mud, (as

a lion is known by his claws,) have afterwards been able to distinguish

him by the same marks from every other; some, too, from the foot-prints

of deer, seen for the first time, will draw inferences as to the size,

and grease, and power of the stag which has left them; saying whether he

were full of strength, or weary from having been hunted; and farther,

whether the prints are those of a buck or a doe. I shall say thus much

more: there are some who, in hunting, when there are some forty hounds

upon the trace of the game, and all are giving tongue together, will

nevertheless, and from a distance, tell which dog is at the head of the

pack, which at the tail, which chases on the hot scent, which is running

off at fault; whether the game is still running, or is at bay; whether

the stag have run far, or have but just been raised from his lair. And

all this amid the din of dogs, and men, and horns, and surrounded by an

unknown and gloomy wood. We should not, therefore, be greatly surprised

when we see those who have experience telling by what hen each

particular egg in a number has been laid. I wish there were some equally

ready way from the child of knowing the true father.

The principal difference between eggs, however, is their fecundity or

barrenness--the distinction of fruitful eggs from hypenemic,

adventitious, or wind eggs. Those eggs are called hypenemic, (as if the

progeny of the wind,) that are produced without the concourse of the

male, and are unfit for setting; although Varro[161] declares that the

mares, in Lusitania, conceive by the wind. For zephyrus was held a

fertilizing wind, whence its name, as if it were ζωηφερὀς, or life

bringing. So that Virgil says:

And Zephyrus, with warming breath resolves

The bosom of the ground, and melting rains

Are poured o’er all, and every field brings forth.

Hence the ancients, when with this wind blowing in the spring season,

they saw their hens begin laying, without the concurrence of the cock,

conceived that zephyrus, or the west wind, was the author of their

fecundity. There are also what are called addle, and dog-day eggs,

produced by interrupted incubation, and so called because eggs often rot

in the dog-days, being deserted by the hens in consequence of the

excessive heat; and also because at this season of the year thunder is

frequent; and Aristotle[162] asserts that eggs die if it thunders whilst

the hen is sitting.

Those eggs are regarded as prolific, which, no unfavorable circumstances

intervening, under the influence of a gentle heat, produce chicks. And

this they will do, not merely through the incubation of the mother, but

of any other bird, if it be but of sufficient size to cherish and cover

them, or by a gentle temperature obtained in any way whatever. “Eggs are

hatched with the same celerity,” says Aristotle,[163] “spontaneously in

the ground, as by incubation. Wherefore in Egypt, it is the custom to

bury them in dung, covered with earth. And there was a tale in Syracuse,

of a drunken fellow, who was accustomed to continue his potations until

a number of eggs, placed under a mat bestrewed with earth, were

hatched.” The empress Livia, is also said to have carried an egg in her

bosom until a chick was produced from it. And in Egypt, and other

countries, at the present time, chickens are reared from eggs placed in

ovens. “The egg, therefore,” as Fabricius[164] truly says, “is not only

the uterus, and place where the generation of the chick proceeds, but it

is that upon which its whole formation depends; and this the egg

accomplishes as agent, as matter, as instrument, as place, and as all

else that concurs.”

For it is certain that the chick is formed by a principle inherent in

the egg, and that nothing accrues to a perfect egg from incubation,

beyond the warmth and protection; in the same way as to the chick when

disclosed, the hen gives nothing more than her warmth and her care, by

which she defends it from the cold and from injury, and directs it to

its proper food. The grand desideratum, therefore, once the chickens are

hatched, is that the hen lead them about, seek for and supply them with

proper food, and cherish them under her wings. And this you will not

easily supply by any kind of artifice.

Capons, and hybrids between the common fowl and the pheasant, produced

in our aviaries, will incubate and hatch a set of eggs; but they never

know how to take care of the brood--to lead them about properly, and to

provide with adequate care for their nurture.

And here I would pause for a moment, (for I mean to treat of the matter

more fully by and by,) to express my admiration of the perseverance and

patience with which the females of almost every species of bird, sit

upon the nest for so many days and nights incessantly, macerating their

bodies, and almost destroying themselves from want of food; what dangers

they will face in defence of their eggs, and when compelled to quit them

for ever so short a time, through necessity, with what eagerness and

haste they return to them again, and brood over them! Ducks and geese,

when they quit the nest for a few minutes, cover and conceal it with

straw. With what true magnanimity do these ill-furnished mothers defend

their eggs! which, after all, perhaps, are mere wind or addle eggs, or

not their own, or artificial eggs of chalk or ivory;--it is still the

same, they defend all with equal courage. It is truly a remarkable love

which birds display for inert and lifeless eggs; and their solicitude is

repaid by no kind of advantage or enjoyment. Who does not wonder at the

affection, or passion rather, of the clucking hen, which can only be

extinguished by a drenching with cold water. In this state of her

feeling she neglects everything,--her wings droop, her feathers are

unpruned and ruffled, she wanders about restless and dissatisfied,

disturbing other hens on their nests, seeking eggs everywhere, which she

commences forthwith to incubate; nor will she be at peace until her

desire has been gratified, until she has a brood to lead about with her,

upon which she may expend her fervour, which she may cherish, feed, and

defend. How pleasantly are we moved to laughter when we see the poor hen

following to the water the supposititious brood of ducklings she has

hatched, wandering restlessly round the pool, attempting to wade after

them to her own imminent peril, and by her noises and various artifices

striving to entice them back to the shore!

According to Aristotle,[165] barren eggs do not produce chicks because

their fluids do not thicken under incubation, nor is the yelk or the

white altered from its original constitution. But we shall revert to

this subject in our general survey of generation.

Our housewives, that they may distinguish the eggs that are addled from

those that will produce chicks, take them from the fourteenth to the

sixteenth day of the incubation, and drop them softly into tepid water,

when the spoilt ones sink, whilst the fruitful ones swim. If the

included chick be well forward, and moves about with alacrity, the egg

not only rolls over but even dances in the water. And if you apply the

egg to your ear for several days before the hatching, you may hear the

chick within kicking, scratching, and even chirping. When the hen that

is sitting hears these noises, she turns the eggs and lays them

otherwise than they were, until the chicks, getting into a comfortable

position, become quiet; even as watchful mothers are wont to treat

their infants when they are restless and cry in their cradles.

Hens lay eggs in variable numbers: “Some hens,” says the

philosopher,[166] “except the two winter months, lay through the whole

year; some of the better breeds will lay as many as sixty eggs before

they show a disposition to sit; though these eggs are not so prolific as

those of the commoner kinds. The Adrianic hens are small, and lay every

day, but they are ill-tempered, and often kill their young ones; they

are particoloured in their plumage. Some domestic fowls will even lay

twice a day; and some, by reason of their great fecundity, die young.”

In England some of the hens lay every day; but the more prolific

commonly lay two days continuously and then miss a day: the first day

the egg is laid in the morning, next day in the afternoon, and the third

day there is a pause. Some hens have a habit of breaking their eggs and

deserting their nests; whether this be from disease or vice is not

known.

Certain differences may also be observed in the incubation: some fowls

only sit once, others twice, or thrice, or repeatedly. Florentius says,

that in Alexandria, in Egypt, there are fowls called monosires, from

which the fighting cocks are descended, which go on sitting for two or

three periods, each successive brood being removed as it is hatched, and

brought up apart. In this way the same hen will hatch forty, sixty, and

even a greater number of chickens, at a single sitting.

Some eggs too, are larger, others smaller; a few extremely small; these,

in Italy, are commonly called centenina; and our country folks still

believe that such eggs are laid by the cock, and that were they set they

would produce basilisks. “The vulgar,” says Fabricius,[167] “think that

this small egg is the last that will be laid, and that it comes as the

hundredth in number, whence the name; that it has no yelk, though all

the other parts are present--the chalazæ, the albumen, the membranes,

and the shell. And it seems probable that it is produced when all the

other yelks have been fashioned into eggs, and no more remain in the

vitellary; on the other hand, however, a modicum of albumen remains, and

out of this, it may be inferred, is the small egg in question produced.”

To me, nevertheless, this does not appear likely; because it is certain

that the whole ovary being removed, the uterus secundus also diminishes

in size in the same proportion, and shrinks into a mere membrane, which

contains neither any fluid nor any albumen. Fabricius proceeds: “The ova

centenina are met with of two kinds: one of them being without a yelk,

and this is the true centenine egg, because it is the last which the hen

will lay at that particular season--she will now cease from laying for a

time. The other is also a small egg, but it has a yelk, and will not

prove the last which the hen will then lay, but is intermediate between

those of the usual size that have preceded, and others that will follow.

It is of small size because there has been a failure of the vegetative

function, as happens to the peach, and other fruit, of which we see many

of adequate size, but a few that are very diminutive.” This may be in

consequence of the inclemency of the weather, or the want of sun, or

from defective nutriment in point either of quantity or quality. I

should not readily allow, however, that the eggs last laid are always

small.

Monstrous eggs are not wanting; “for the augurs,” says Aristotle,[168]

“held it portentous when eggs were laid that were all yellow; or when,

on a fowl being laid open, eggs were found under the septum transversum,

where the rudimentary eggs of the female usually appear, of the

magnitude of perfect eggs.”

To this head may be referred those eggs that produce twins, that have

two yelks. Such an egg I lately found in the uterus of a fowl, perfect

in all respects, and covered with a shell; the yelks, cicatriculæ, and

thicker albuminous portions being all double, and the chalazæ present in

two pairs: a single thinner albumen, however, surrounded all these, and

this in its turn was included within the usual double common membrane,

and single shell. For, indeed, although Aristotle says that fowls always

lay some eggs of this kind, I shall hardly be induced to believe that

this does not occur against the ordinary course of nature. And although

twin chicks are produced from such eggs as I have ascertained in

opposition to the opinion of Fabricius, who says that they produce

chicks having four legs, or four wings and two heads, which, however,

are not capable of living, but for the most part speedily die, either

by reason of want of room or of air in the shell, or because the one

proves a hinderance to the other and blights it; nor can it happen that

both should be equally prepared for exclusion--that one should not prove

an abortion.

Briefly and summarily the differences among eggs are principally of

three kinds: some are prolific, some unprolific; some will produce males

and some females; some are the produce of the two sexes of the same

species, others of allied species and will produce hybrids, such as we

see between the common hen and the pheasant, the progeny being

referrible either to the first or to the last male that had connexion

with the hen. Because, according to Aristotle,[169] “the egg, which

receives its constitution by intercourse, passes from its own into

another genus, if the hen be trodden when she carries either an

adventitious egg or one that was conceived under the influence of

another male, and this renewed intercourse take place before the yellow

is changed into the white. So that hypenemic or wind eggs are made

fruitful, and fruitful eggs receive the form of the male which has

connexion last. But if the change has taken place into the white, it

cannot happen either that the wind egg is turned into a fertile one, or

that the egg which is contained in the uterus in virtue of a previous

intercourse, shall be altered into the genus of the male which has the

second communication.” For the seminal fluid of the cock, as Scaliger

wittily remarks, is like a testament, the last will or disposition in

which is that which stands in force.

To these particulars it might perhaps be added, that some eggs are more

strong and lusty than others, more full of life, if the expression may

be used; though as there is a vital principle in the egg, so must there

inhere the corresponding virtue that flows from it. For, as in other

kinds of animals, some of the females are so replete with desire, so

full of Venus, that they conceive from any and every intercourse, even

once submitted to, and from a weakly male, and produce several young

from the same embrace; others, on the contrary, are so torpid and

sluggish, that unless they are assailed by a vigorous male, under the

influence of strong desire, and that not once, but repeatedly, and for

a certain time, they continue barren. This is also the case with eggs,

some of which, though they may have been conceived in consequence of

intercourse, still remain unprolific unless perfected by repeated and

continued connections. Whence it happens that some eggs are more

speedily changed by incubation than others, exhibiting traces of the

fœtus from the third day; others again, either become spoiled, or suffer

transformation into the fœtus more slowly, exhibiting no indications of

the future chick even up to the seventh day, as shall be made to appear

by and by, in speaking of the generation of the chick from the egg.

Thus far have we discoursed of the uterus of the fowl, and its function;

of the production of the hen’s egg, and of its differences and

peculiarities, from immediate observation; and from the instances

quoted, conclusions may be drawn with reference to other oviparous

animals.

We have now to pursue the history of the generation and formation of the

fœtus from the egg. For indeed, as I have said above, the entire

contemplation of the family of birds is comprehended in these two

propositions: how is an egg engendered of a male and female; and by what

process do males and females proceed from eggs?--the circle by which,

under favour of nature, their kinds are continued to eternity.

EXERCISE THE FOURTEENTH.

_Of the production of the chick from the egg of the hen._

Of the growth and generation of the hen’s egg enough has already been

said; and we have now to lay before the reader our observations on the

procreation of the chick from the egg,--a duty which is equally

difficult, and profitable, and pleasant. For in general the first

processes of nature lie hid, as it were, in the depths of night, and by

reason of their subtlety escape the keenest reason no less than the most

piercing eye.

Nor in truth is it a much less arduous business to investigate the

intimate mysteries and obscure beginnings of generation than to seek to

discover the frame of the world at large, and the manner of its

creation. The eternity of things is connected with the reciprocal

interchange of generation and decay; and as the sun, now in the east and

then in the west, completes the measure of time by his ceaseless

revolutions, so are the fleeting things of mortal existence made eternal

through incessant change, and kinds and species are perpetuated though

individuals die.

The writers who have treated of this subject have almost all taken

different paths; but having their minds preoccupied, they have hitherto

gone to work to frame conclusions in consonance with the particular

views they had adopted.

Aristotle,[170] among the ancients, and Hieron. Fabricius of

Aquapendente, among the moderns, have written with so much accuracy on

the generation and formation of the chick from the egg that little seems

left for others to do. Ulyssus Aldrovandus,[171] nevertheless, described

the formation of the chick in ovo; but he appears rather to have gone by

the guidance of Aristotle than to have relied on his own experience. For

Volcherus Coiter, living at this time in Bologna, and encouraged, as he

tells us, by Aldrovandus, his master, opened incubated eggs every day,

and illustrated many points besides those noted by Aldrovandus;[172]

these discoveries, however, could scarcely have remained unknown to

Aldrovandus. Æmilius Parisanus, a Venetian physician, having discarded

the opinions of others, has also given a new account of the formation of

the chick from the egg.

But since our observations lead us to conclude that many things of great

consequence are very different from what they have hitherto been held to

be, I shall myself give an account of what goes on in the egg from day

to day, and what parts are there transmuted, directing my attention to

the first days especially, when all is most obscure and confused, and

difficult of observation, and in reference to which writers have more

particularly drawn the sword against one another in defence of their

several discordant observations, which, in sooth, they accommodate

rather to their preconceived opinions respecting the material and

efficient cause of animal generation than to simple truth.

What Aristotle says on the subject of the reproduction of the chick in

ovo is perfectly correct. Nevertheless, as if he had not himself seen

the things he describes, but received them at second hand from another

expert observer, he does not give the periods rightly; and then he is

grievously mistaken in respect of the place in which the first rudiments

of the egg are fashioned, stating this to be the sharp end, for which he

is fairly challenged by Fabricius. Neither does he appear to have

observed the commencement of the chick in the egg; nor could he have

found the things which he says are necessary to all generation in the

place which he assigns them. He will, for instance, have it that the

white is the constituent matter (since nothing naturally can by

possibility be produced from nothing.) And he did not sufficiently

understand how the efficient cause (the seminal fluid of the cock,)

acted without contact; nor how the egg could, of its own accord, without

any inherent generative matter of the male, produce a chick.

Aldrovandus, adopting an error akin to that of Aristotle, says besides,

that the yelk rises during the first days of the incubation into the

sharp end of the egg, a proposition which no eyes but those of the blind

would assent to; he thinks also that the chalazæ are the semen of the

cock, and that the chick arises from them, though it is nourished both

by the yelk and the white. In this he is obviously in opposition to

Aristotle, who held that the chalazæ contributed nothing to the

reproductive powers of the egg.

Volcherus Coiter is, on the whole, much more correct; and his statements

are far more consonant with what the eye perceives. But his tale of the

three globules is a fable. Neither did he rightly perceive the true

commencement of the chick in ovo.

Hieronymus Fabricius contends that the chalazæ are not the sperma of the

cock; but then he will have it that “from these, fecundated by the

seminal fluid of the cock, as from the appropriate matter, the chick is

incorporated.” Fabricius observed the point of origin of the chick, the

spot or cicatricula, namely, which presents itself upon the tunica

propria of the yelk; but he regarded it as a cicatrice or scar left on

the place where the peduncle had been attached; he viewed it as a

blemish in the egg, not as any important part.

Parisanus completely refutes Fabricius’s ideas of the chalazæ; but he

himself obviously raves when he speaks of certain circles, and

principal parts of the fœtus, viz., the liver and heart. He appears to

have observed the commencement of the fœtus in ovo; but what it was he

obviously did not know, when he says, “that the white point in the

middle of the circles is the semen of the cock, from which the chick is

produced.”

Thus it comes to pass that every one, in adducing reasons for the

formation of the chick in ovo, in accordance with preconceived opinions,

has wandered from the truth. Some will have it that the semen or the

blood is the matter whence the chick is engendered; others, that the

semen is the agent or efficient cause of its formation. Yet to him who

dispassionately views the question is it quite certain that there is no

prepared matter present, nor any menstruous blood to be coagulated at

the time of intercourse by the semen masculinum, as Aristotle will have

it; neither does the chick originate in the egg from the seed of the

male, nor from that of the female, nor from the two commingled.

EXERCISE THE FIFTEENTH.

_The first examination of the egg; or of the effect of the first day’s

incubation upon the egg._

That we may be the more clearly informed of the effect which the first

day’s incubation produces upon the egg, we must set out by ascertaining

what changes take place in an egg spontaneously, changes that

distinguish a stale egg from one that is new-laid, when what is due to

the incubation _per se_ will first be clearly apprehended.

The space or cavity in the blunt end is present, as we have said, in

every egg; but the staler the egg the larger does this hollow

continually grow; and this is more especially the case when eggs are

kept in a warm place, or when the weather is hot; the effect being due

to the exhalation of a certain portion of the thinner albumen, as has

been stated in the history of the egg. This cavity, as it increases,

extends rather in the line of the length than of the breadth of the egg,

and comes finally to be no longer orbicular.

The shell, already less transparent, becomes dingy.

The albumen grows thicker and more viscid, and acquires a straw or

yellow colour.

The tunica propria of the vitellus becomes more lax, and appears

wrinkled, for it seems that some even of this fluid is dissipated in the

course of time.

The chalazæ are found in either end of every egg, in the same situation,

and having the same consistence--whether the egg be recent or stale,

fruitful or barren, it does not signify; by their means a firm connexion

is established between the yelk and the white, and the two fluids

preserve their relative positions. The chalazæ, indeed, are two mutually

opposed supports or poles, and hinges of this microcosm; and are

constructed as if made up of numerous coats of the albumen, twisted

together at either end into a knotted rope, by which they are attached

to the vitellus. And hence it happens that the yelk is separated from

the white with difficulty, unless the chalazæ are either first divided

with a knife or torn with the fingers; this done, the white immediately

falls away from the yelk. It is by means of these hinges that the

vitellus is both retained in the centre of the egg and preserved of its

proper consistence. And they are so connected that the principal part,

the cicatricula, to wit, always regards the same region of the egg, or

its upper part, and is preserved equidistant from either end. For this

spot or cicatricula is observed to be of the same consistence,

dimensions, and colour, and in the same situation in the stale as in the

new-laid egg. But as soon as the egg, under the influence of the gentle

warmth of the incubating hen, or of warmth derived from another source,

begins to pullulate, this spot forthwith dilates, and expands like the

pupil of the eye, and from thence, as the grand centre of the egg, the

latent plastic force breaks forth and germinates. This first

commencement of the chick, however, so far as I am aware, has not yet

been observed by any one.

On the second day of the incubation, after the egg has been exposed to

warmth for twenty-four hours, under the hen, as the cavity in the blunt

end has enlarged greatly and descended, so has the internal constitution

of the egg also begun to be changed. The yelk, which had hitherto lain

in the middle of the albumen, rises towards the blunt end, and its

middle, where the cicatricula is situated, is lifted up and applied to

the membrane that bounds the empty space, so that the yelk now appears

to be connected with the cavity by means of the cicatricula; and in the

same measure as the yelk rises does the thicker portion of the albumen

sink into the sharp or lower end of the egg. Whence it appears, as

Fabricius rightly remarks, that Aristotle[173] was either in error, or

that there is a mistake in the codex, when it is said, “In this time”

(viz., between three and four days, and as many nights,) “the yelk is

brought to the summit, where the commencement of the egg is, and the egg

is exposed in this part,” i. e. under the enlarged empty space. Now

Aristotle[174] calls the principium ovi, or commencement of the egg, its

smaller end, which is last extruded. But it is certain that the yelk

ascends towards the blunt end of the egg, and that the cavity there

enlarges. And Aldrovandus is undoubtedly in error when he speaks as if

he had experience of the fact, and says that the yelk rises to the sharp

end. I will confess, nevertheless, that on the second or third day I

have occasionally observed the cicatricula expanded and the beginning of

the chick already laid, the yelk not having yet risen; this, however,

happens rarely, and I am inclined to ascribe it to some weakness in the

egg.

On the second day of the incubation, or first day of inspection, the

cicatricula in question is found to have enlarged to the dimensions of a

pea or lentil, and is divided into circles, such as might be drawn with

a pair of compasses, having an extremely minute point for their centre.

It is very probable that Aldrovandus observed this spot, for he says:

“In the midst of the yellow a certain whitish something makes its

appearance, which was not noticed by Aristotle;” and also by Coiter,

when he expresses himself thus: “On the second day there is in the

middle of the yelk a part whiter than the rest;” Parisanus, too, may

have seen it; he observes: “In the course of the second day I observe a

white body of the size and form of a middling lentil; and this is the

semen of the cock covered over with a white and most delicate tunic,

which underlies the two common membranes of the entire egg, but overlies

the tunica propria of the yelk.” I believe, however, that no one has yet

said that this cicatricula occurs in every egg, or has acknowledged it

to be the origin of the chick.

Meantime the chalazæ or treadles will be seen to decline from either end

of the egg towards its sides, this being occasioned by that alteration

which we have noticed in the relative situations of the two fluids. The

treadle from the blunt end descends somewhat; the one from the sharp end

rises in the same proportion: as in a globe whose axis is set obliquely,

one pole is as much depressed below the horizon as the other is raised

above it.

The vitellus, too, particularly in the situation of the cicatricula,

begins to grow a little more diffluent than it was, and raises its

tunica propria, (which we have found in stale eggs before incubation to

be somewhat lax and wrinkled,) into a tumour; and it now appears to have

recovered the same colour, consistency, and sweetness of taste that it

had in the egg just laid.

Such is the process in the course of the first day that leads to the

production of a new being, such the earliest trace of the future chick.

Aldrovandus adds: “the albumen suffers no change,” which is correct; but

when he asserts that “the semen of the cock can be seen in it,” he as

manifestly errs. Resting on a most insufficient reason, he thought that

the chalazæ were the semen of the cock, “because,” forsooth, “the eggs

that are without chalazæ are unfruitful.” This I can very well believe;

for these were then no proper eggs; for all eggs, wind eggs as well as

those that are prolific, have chalazæ. But he, misled perhaps by the

country women, who in Italian call the chalazæ _galladura_, fell into

the vulgar error. Nor is Hieronymus Fabricius guilty of a less grave

mistake when he exhibits the formation of the chick in a series of

engravings, and contends that it is produced from the chalazæ;

overlooking the fact that the chalazæ are present the whole of the time,

and unchanged, though they have shifted their places; and that the

commencement of the chick is to be sought for at a distance from them.

EXERCISE THE SIXTEENTH.

_Second inspection of the egg._

The second day gone by, the circles of the cicatricula that have been

mentioned, have become larger and more conspicuous, and may now be of

the size of the nail of the ring-finger, sometimes even of that of the

middle finger. By these rings the whole cicatricula is indistinctly

divided into two, occasionally into three regions, which are frequently

of different colours, and bear a strong resemblance to the cornea of the

eye, both as respects dimensions, a certain degree of prominence, and

the presence of a transparent and limpid fluid included within it. The

centre of the cicatricula here stands for the pupil; but it is occupied

with a certain white speck, and appears like the pupil of some small

bird’s eye obscured by a suffusion or cataract, as it is called. On this

account we have called the entire object the oculum ovi, the eye of the

egg.

Within the circles of the cicatricula, I say, there is contained a

quantity of perfectly bright and transparent fluid, even purer than any

crystalline humour; which, if it be viewed transversely and against the

light, the whole spot will rather appear to be situated in the albumen

than sunk into the membrane of the yelk, as before: it presents itself

as a portion of the albumen dissolved and clarified, and included within

a most delicate tunica propria. Hence I entitle this fluid the oculum

seu colliquamentum album; it is as if a portion of the albumen,

liquefied by the heat, shone apart, (which it does, unless disturbed by

being shaken,) and formed a more spirituous and better digested fluid,

separated from the rest of the albumen by a tunica propria, and situated

between the two masses of liquid, the yelk and the albumen. It differs

from the rest of the albumen by its clearness and transparency, as the

water of a pellucid spring differs from that of a stagnant pool. The

tunic which surrounds this fluid is so fragile and delicate that, unless

the egg be handled with great care, it is apt to give way, when the pure

spring is rendered turbid by a mixture of fluids.

I was long in doubt what I should conclude as to this clear diffluent

fluid, whether I should regard it as the innate heat, or radical

moisture; as a matter prepared for the future fœtus, or a

perfectly-concocted nourishment, such as dew is held to be among the

secondary humours. For it is certain, as shall be afterwards shown, that

the earliest rudiments of the fœtus are cast in its middle, that from

this the chick derives its first nutriment, and even when of larger size

continues to live amidst it.

This solution therefore increases rapidly in quantity, particularly in

its internal region, which, as it expands, forces out and obliterates

the external regions. This change is effected in the course of a single

day, as is shown in the second figure of Fabricius. It is very much as

it is with the eyes of those animals which have a very ample pupil, and

see better by night than by day, such as owls, cats, and others, whose

pupils expand very much in the dusk and dark, and, on the contrary,

contract excessively in a brilliant light: one of these animals being

taken quickly from a light into a shady place, the pupil is seen to

enlarge in such wise that the coloured ring, called the iris, is very

much diminished in size, and indeed almost entirely disappears.

Parisanus, falling upon these regions, is grossly mistaken when he

speaks of “a honey-coloured, a white, a gray, and another white circle;”

and says that “the fœtus is formed from the white middle point” (which,

indeed, appears in these regions), and that “this is the semen of the

cock.” That he may exalt himself on a more notable subtlety he

continues: “Before any redness is apparent in the body of the fœtus, two

minute vesicles present themselves in it; in the beginning, however,

neither of them is tinged with red;” one of these he would have us

receive as the heart, the other as the liver. But in truth there is

neither any vesicle present sooner than the redness of the blood is

disclosed; nor does the embryo ever suddenly become red in the course of

the first days of its existence; nor yet does any of these vesicles

present us with a trace of the liver. Both of them belong, in fact, to

the heart, prefiguring its ventricles and auricles, and palpitating, as

we shall afterwards show, they respond reciprocally by their systoles

and diastoles.

Aristotle[175] appears to have known this dissolved fluid, when he says:

“A membrane, too, marked with sanguineous fibres, surrounds the white

fluid at this time (the third day), arising from those orifices of the

veins.” Now the philosopher can neither be supposed by the words “white

fluid,” to refer to the albumen at large, because at this period the

membrane of the white is not yet covered with veins; it is only the

membrane of the dissolved fluid which appears with a few branches of

veins distributed over it here and there. And because he says: “this

membrane, too,” as if he understood another than those which he had

spoken of as investing the albumen and the yelk before incubation, and

designated this one as first arising after the third day, and from the

orifices of the veins.

Coiter seems also to have known of this dissolved fluid; he says: “A

certain portion of the albumen acquiring a white colour, another

becoming thicker.” The fluid in question is surrounded with its proper

membrane, and is distinct and separate from the rest of the albumen

before there is any appearance of blood. We shall have occasion, by and

by, to speak of the singular importance of this fluid to the fœtuses of

every animal. Whilst they float in it they are safe from succussion and

contusion, and other external injury of every kind; and they moreover

are nourished by it. I once showed to their serene majesties the king

and queen, an embryo, the size of a French-bean, which had been taken

from the uterus of a doe; all its membranes were entire, and from its

genital organs we could readily tell that it was a male. It was, in

truth, a most agreeable natural spectacle; the embryo perfect and

elegant, floating in this pure, transparent, and crystalline fluid,

invested with its pellucid tunica propria, as if in a glass vessel of

the greatest purity, of the size of a pigeon’s egg.

EXERCISE THE SEVENTEENTH.

_The third inspection of the egg._

Having seen the second process or preparation of the egg, towards the

production of the embryo which presents itself in the course of the

third day, we proceed to the Third Stage, which falls to be considered

after the lapse of three days and as many nights. Aristotle[176] says:

“Traces of generation commence in the egg of the hen after three days

and three nights [of incubation];” for example, on Monday morning, if in

the morning of the preceding Friday the egg has been put under the hen.

This stage forms the subject of the third figure in Fabricius.

If the inspection of the egg be made on the fourth day, the

metamorphosis is still greater, and the change likewise more wonderful

and manifest with every hour in the course of the day. It is in this

interval that the transition is made in the egg from the life of the

plant to the life of the animal. For now the margin of the diffluent

fluid looks red, and is purpurescent with a sanguineous line, and nearly

in its centre there appears a leaping point, of the colour of blood, so

small that at one moment, when it contracts, it almost entirely escapes

the eye, and again, when it dilates, it shows like the smallest spark of

fire. Such at the outset is animal life, which the plastic force of

nature puts in motion from the most insignificant beginnings!

The above particulars you may perceive towards the close of the third

day, with very great attention, and under favour of a bright light (as

of the sun), or with the assistance of a magnifying glass. Without these

aids you would strain your eyes in vain, so slender is the purple line,

so slight is the motion of the palpitating point. But at the beginning

of the fourth day you may readily, and at its close most readily,

perceive the “palpitating bloody point, which already moves,” says

Aristotle, “like an animal, in the transparent liquid (which I call

colliquamentum); and from this point two vascular branches proceed, full

of blood, in a winding course” into the purpurescent circle and the

investing membrane of the resolved liquid; distributing in their

progress numerous fibrous offshoots, which all proceed from one

original, like the branches and twigs of a tree from the same stem.

Within the entering angle of this root, and in the middle of the

resolved liquid, is placed the red palpitating point, which keeps order

and rhythm in its pulsations, composed of [alternate] systoles and

diastoles. In the diastole, when it has imbibed a larger quantity of

blood, it becomes enlarged, and starts into view; in the systole,

however, subsiding instantaneously as if convulsed by the stroke, and

expelling the blood, it vanishes from view.

Fabricius depicts this palpitating point in his third figure; and

mistakes it--a thing which is extraordinary--for the body of the embryo;

as if he had never seen it leaping or pulsating, or had not understood,

or had entirely forgotten the passage in Aristotle. A still greater

subject of amazement, however, is his total want of solicitude about his

chalazæ all this while, although he had declared the rudiments of the

embryo to be derived from them.

Ulyssus Aldrovandus,[177] writing from Bologna nearly at the same time,

says: “There appears in the albumen, as it were, a minute palpitating

point, which The Philosopher declares to be the heart. And I have

unquestionably seen a venous trunk arising from this, from which two

other branches proceeded; these are the blood-vessels, which he says

extend to either investing membrane of the yelk and white. And I am

myself entirely of his opinion, and believe these to be veins, and

pulsatile, and to contain a purer kind of blood, adapted to the

production of the principal parts of the body, the liver, to wit, the

lungs, and others of the same description.” Both of the vessels in

question, however, are not veins, neither do they both pulsate; but one

of them is an artery, another a vein, as we shall see by and by, when we

shall farther show that these passages constitute the umbilical vessels

of the embryo.

Volcher Coiter has these words: “The sanguineous point or globule, which

was formerly found in the yelk, is now observed more in the albumen, and

pulsates distinctly.” He says, erroneously, “formerly found in the

yelk;” for the point discovered in the vitellus is white, and does not

pulsate; nor does the sanguineous point or globe appear to pulsate at

the end of the second day of incubation. But the point which we have

indicated in the middle of the circle, and as constituting its centre in

connexion with the vitellus, disappears before that point which is

characterized by Aristotle as palpitating, can be discerned; or, as I

conceive, having turned red, begins to pulsate. For both points are

situated in the centre of the resolved fluid, and near the root of the

veins which thence arise; but they are never seen simultaneously: in the

place of the white point there appears a red and palpitating point.

That portion of Coiter’s sentence, however, where he says: “the punctus

saliens is now seen in the albumen rather than in the yelk,” is

perfectly accurate. And, indeed, moved by these words, I have inquired

whether the white point in question is turned into the blood-red point,

inasmuch as both are nearly of the same size, and both make their

appearance in the same situation. And I have, indeed, occasionally found

an extremely delicate bright purple circle ending near the ruddy horizon

surrounding the resolved liquid, in the centre of which there was the

white point, but not the red and pulsating point apparent; for I have

never observed these two points at one and the same time. It were

certainly of great moment to determine: Whether or not the blood was

extant before the pulse? and whether the pulsating point arose from the

veins, or the veins from the pulsating point?

So far as my observations enable me to conclude, the blood has seemed to

go before the pulse. This conclusion is supported by the following

instance: on Wednesday evening I set three hen’s eggs, and on Saturday

evening, somewhat before the same hour, I found these eggs cold, as if

forsaken by the hen: having opened one of them, notwithstanding, I found

the rudiments of an embryo, viz., a red and sanguinolent line in the

circumference; and in the centre, instead of a pulsating point, a white

and bloodless point. By this indication I saw that the hen had left her

nest no long time before; wherefore, catching her, and shutting her up

in a box, I kept her upon the two remaining eggs, and several others,

through the ensuing night. Next morning, very early, both of the eggs

with which the experiment was begun, had revived, and in the centre

there was the pulsating point, much smaller than the white point, from

which, like a spark darting from a cloud, it made its appearance in the

diastole; it seemed to me, therefore, that the red point emanated from

the white point; that the punctum saliens was in some way engendered in

that white point; that the punctum saliens, the blood being already

extant, was either originally there produced, or there began to move. I

have, indeed, repeatedly seen the punctum saliens when all but dead,

and no longer giving any signs of motion, recover its pulsatile

movements under the influence of renewed warmth. In the order of

generation, then, I conceive that the punctum and the blood first exist,

and that pulsation only occurs subsequently.

This at all events is certain, that nothing whatever of the future fœtus

is apparent on this day, save and except certain sanguineous lines, the

punctum saliens, and those veins that all present themselves as

emanating from a single trunk, (as this itself proceeds from the punctum

saliens,) and are distributed in numerous branches over the whole of the

colliquament or dissolved fluid. These vessels afterwards constitute the

umbilical vessels, by means of which, distributed far and wide, the

fœtus as it grows obtains its nourishment from the albumen and vitellus.

You have a striking example of similar vessels and their branchings in

the leaves of trees, the whole of the veins of which arise from the

peduncle or foot-stalk, and from a single trunk are distributed to the

rest of the leaf.

The entire including membrane of the colliquament traversed by

blood-vessels, corresponds in form and dimensions with the two wings of

a moth; and this, in fact, is the membrane which Aristotle[178]

describes as “possessing sanguineous fibres, and at the same time

containing a limpid fluid, proceeding from those mouths of the veins.”

Towards the end of the fourth day, and the beginning of the fifth, the

blood-red point, increased into a small and most delicate vesicle, is

perceived to contain blood in its interior, which it propels by its

contractions, and receives anew during its diastoles.

Up to this point I have not been able to perceive any difference in the

vessels: the arteries are not distinguished from the veins, either by

their coats or their pulsations. I am therefore of opinion, that all the

vessels may be spoken of indifferently under the name of veins, or,

adopting Aristotle’s[179] term, of venous canals.

“The punctum saliens,” says Aristotle, “is already possessed of

spontaneous motion, like an animal.” Because an animal is distinguished

from that which is none, by the possession of sense and motion. When

this point begins to move for the first time, consequently, we say well

that it has assumed an animal nature; the egg, originally imbued with a

vegetative soul, now becomes endowed in addition with a motive and

sensitive force; from the vegetable it passes into the animal; and at

the same time the living principle, which fashions the chick from the

egg, and afterwards gives it the measure of intelligence it manifests,

enters into the embryo. For, from the actions or manifestations, The

Philosopher[180] concludes demonstratively, that the faculties or powers

of acting are inherent, and through these the cause and principle of

life, the soul, to wit, and the actions, inasmuch as manifestation is

action.

I am myself farther satisfied from numerous experiments, that not only

is motion inherent in the punctum saliens, which indeed no one denies,

but sensation also. For on any the slightest touch, you may see the

point variously commoved, and, as it were, irritated; just as sensitive

bodies generally give indications of their proper sensations by their

motions; and, the injury being repeated, the punctum becomes excited and

disturbed in the rhythm and order of its pulsations. Thus do we conclude

that in the sensitive-plant, and in zoophytes, there is inherent

sensibility, because when touched they contract, as if they felt

uncomfortable.

I have seen, I repeat, very frequently, and those who have been with me

have seen this punctum, when touched with a needle, a probe, or a

finger, and even when exposed to a higher temperature, or a severer

cold, or subjected to any other molesting circumstance or thing, give

various indications of sensibility, in the variety, force, and frequency

of its pulsations. It is not to be questioned, therefore, that this

punctum lives, moves, and feels like an animal.

An egg, moreover, too long exposed to the colder air, the punctum

saliens beats more slowly and languidly; but the finger, or some other

warmth being applied, it forthwith recovers its powers. And farther,

after the punctum has gradually languished, and, replete with blood, has

even ceased from all kind of motion, or other indication of life, still,

on applying my warm finger, in no longer a time than is measured by

twenty beats of my pulse, lo! the little heart is revivified, erects

itself anew, and, returning from Hades as it were, is restored to its

former pulsations. The same thing happens through heat applied in any

other way--that of the fire, or of hot water--as has been proved by

myself and others again and again; so that it seemed as if it lay in our

power to deliver the poor heart over to death, or to recall it to life

at our will and pleasure.

What has now been stated, for the most part comes to pass on the fourth

day from the commencement of the incubation--I say, for the most

part,--because it is not invariably so, inasmuch as there is great

diversity in the maturity of eggs, and some are more speedily perfected

than others. As in trees laden with fruit, some, more forward and

precocious, falls from the branches, and some, more crude and immature,

still hangs firmly on the bough; so are some eggs less forward on the

fifth day than others in the course of the third. This, that I might

give it forth as a thing attested and certain, I have repeatedly

ascertained in numerous eggs, incubated for the same length of time, and

opened on the same day. Nor can I ascribe it to any difference of sex,

or inclemency of weather, or neglect of incubation, or to any other

cause but an inherent weakness of the egg itself, or some deficiency of

the native heat.

Hypenemic or unfruitful eggs, begin to change at this time, as the

critical day when they must show their disposition. As fertile eggs are

changed by the inherent plastic force into colliquament (which

afterwards passes into blood), so do wind-eggs now begin to change and

to putrefy. I have, nevertheless, occasionally observed the spot or

cicatricula to expand considerably even in hypenemic eggs, but never to

rise into a cumulus, nor to become circumscribed by regularly disposed

concentric circles. Sometimes I have even observed the vitellus to get

somewhat clearer, and to become liquefied; but this was unequally; there

were flocks, as if formed by sudden coagulation, swimming dispersed

through it like clouds. And although such eggs could not yet be called

putrid, nor were they offensive, still were they disposed to

putrefaction; and, if continued under the hen, they soon arrived at this

state, the rottenness commencing at the very spot where in fruitful eggs

the reproductive germ appears.

The more perfect or forward eggs then, about the end of the fourth day,

contain a double or bipartite pulsating vesicle, each portion

reciprocating the other’s motion, in such order and manner that whilst

one is contracting, the other is distended with blood and ruddy in

colour; but this last contracting anon forces out its charge of blood,

and, an instant being interposed, the former rises again and repeats its

pulse. And it is easy to perceive that the action of these vesicles is

contraction, by which the blood is moved and propelled into the vessels.

“On the fourth day,” says Aldrovandus,[181] “two puncta are perceived,

both of which are in motion; these, undoubtedly, are the heart and the

liver, viscera which Aristotle allowed to eggs incubated for three

days.”

The Philosopher,[182] however, nowhere says anything of the kind;

neither, for the most part, are the viscera mentioned conspicuous before

the tenth day. And I am indeed surprised that Aldrovandus should have

taken one of these pulsating points for the liver, as if this viscus

were ever moved in any such manner! It seems much better to believe that

with the growth of the embryo one of the pulsating points is changed

into the auricles, the other into the ventricles of the heart. For in

the adult, the ventricles are filled in the same manner by the auricles,

and by their contraction they are straightway emptied again, as we have

shown in our treatise on the Motion of the Heart and Blood.

In more forward eggs, towards the end of the fourth day, I have

occasionally found I know not what cause of obscurity intervening and

preventing me from seeing these pulsating vesicles with the same

distinctness as before; it was as if there had been a haze interposed

between them and the eye. In a clearer light, nevertheless, and with the

use of magnifying glasses, the observations of one day being further

collated with those of the next succeeding day, it was discovered that

the indistinctness was caused by the rudiments of the body,--a nebula

concocted from part of the colliquament, or an effluvium concreting

around the commencements of the veins.

Aldrovandus appears to have observed this: “On the fifth day,” says he,

“the punctum, which we have stated to be the heart, is no longer seen

to move externally, but to be covered over and concealed; still its two

meatus venosi are perceived more distinctly than before, one of them

being, further, larger than the other.” But our learned author was

mistaken here; for this familiar divinity, the heart, enters into his

mansion and shuts himself up in its inmost recesses a long time

afterwards, and when the house is almost completely built. Aldrovandus

also errs when he says, “by the vis insita of the veins, the remaining

portion of the albumen acquires a straw colour,” for this colour is

observed in the thicker albumen of every spoilt egg, and it goes on

increasing in depth from day to day as the egg grows staler, and this

without any influence of the veins, the thinner portion only being

dissipated.

But the embryo enlarging, as we say below, and the ramifications of the

meatus venosi extending far and wide to the albumen and vitellus,

portions of both of these fluids become liquefied, not indeed in the way

Aldrovandus will have it, from some vis insita in the vessels, but from

the heat of the blood which they contain. For into whatsoever part of

either fluid the vessels in question extend, straightway liquefaction

appears in their vicinity; and it is on this account that the yelk about

this epoch appears double: its superior portion, which is in

juxtaposition with the blunt end of the egg, has already become more

diffluent than the rest, and appears like melted yellow wax in contrast

with the other colder firmer portion; like bodies in general in a state

of fusion, it also occupies a larger space. Now this superior portion,

liquefied by the genial heat, is separated from the other liquids of the

egg, but particularly the albumen, by a tunica propria of extreme

tenuity. It therefore happens that if this most delicate, fragile, and

invisible membrane be torn, immediately there ensues an admixture and

confusion of the albumen and vitellus, by which everything is obscured.

And such an accident is a frequent cause of failure in the reproductive

power, (for the different fluids in question are possessed of opposite

natures,) according to Aristotle,[183] in the place already so

frequently referred to: “Eggs are spoiled and become addled in warm

weather especially, and with good reason; for as wine grows sour in hot

weather, the lees becoming diffused through it, (which is the cause of

its spoiling,) so do eggs perish when the yelk spoils, for the lees and

the yelk are the more earthy portion in each. Wherefore wine is

destroyed by an admixture with its dregs, and an egg by the diffusion of

its yelk.”[184] And here, too, we may not improperly refer to that

passage[185] where he says: “When it thunders, the eggs that are under

incubation are spoiled;” for it must be a likely matter that a membrane

so delicate should give way amidst a conflict of the elements. And

perhaps it is because thunder is frequent about the dog days that eggs

which are rotten have been called _cynosura_; so that Columella rightly

informs us that “the summer solstice, in the opinion of many, is not a

good season for breeding chickens.”