[271] EXERCITATIO VIGESIMAPRIMA.
Inspectio post diem decimum.

21th exercise
The inspection after the tenth day

QUAE decimo die conspicienda veniunt, tam accurate ab Aristotele enarrantur, ut vix quidquam supersit quod a nobis addi possit. Sententia autem eius, me paraphraste, est huiusmodi: Decimo iam die pullus totus conspicuus est[1]; atque etiam pellucidus, et albus, praeter oculos, et venarum ramos. Caput etiam toto reliquo corpore maius est; et oculi capite grandiores haerent, seu potius adhaerent, et quasi appenduntur, nulla adhuc pupilla praediti (scilicet perfecte formata, tunicas tamen iam discretas deprehendere non est arduum); quippe tunc si eximas, invenias fabis grandiores, et nigros. A quibus detracta cute humor exit candidus, ac frigidus, vehementer ad lucem refulgens, praeterea vero nihil, in toto capite nempe, praeter dictam aquam limpidam continetur. Ita nimirum se res habet a die septimo ad decimum usque, ut supra diximus.

Those things, showing themselves to the sight at the tenth day, are described in a so accurate way by Aristotle* that hardly anything remains to be added by me. His affirmation, by me paraphrased, sounds this way: «Already at the tenth day the whole chick is visible» and also shining and white except the eyes and the venous branches. «Furthermore the head is larger than the remaining body, and the eyes, larger than the head, stick to it», or better, they are united to it and almost suspended, not yet endowed with any pupil (that is, shaped in a perfect way; nevertheless it is not difficult to recognize the already separate tunics), «and if then you had to remove them, you will find them greater than the broad beans and black. After having removed the wrap a very white and cold liquid escapes, shining in a violent way at the light, but besides this nothing », that is, is contained in the whole head, except the above-mentioned clear water. The things are just so, starting from the seventh day until the tenth, as I previously said.

Eodem tempore, inquit, viscera quoque iam apparent, et quae ad ventris intestinorumque pertinent naturam: cordis nempe parenchyma, pulmones, iecur, et caetera; omnia vero alba, mucilaginosa, et flaccida, nihilque firmitudinis in se habentia. Venaeque etiam quae a corde tendunt, iam umbilico applicantur. Ab umbilico autem tenditur vena una ad membranam qua vitellus continetur: qui eo tempore liquidior iam et fusior est, [272] quam qui natura sua constare solet. Altera autem ad membranam, qua et tota membrana (nempe colliquamenti tunica) foetum ambiens et vitellum, interiacensque humor continetur. Crescente enim paulatim pullo, vitelli pars supra, pars infra est; albumen autem in medio liquidum. Sed et sub inferiore vitelli parte illa, albumen item est; quemadmodum et ante suberat. Hactenus Aristoteles.

He says: «In the same space of time also the viscera already appear and what concerns the nature of abdomen and bowels», that is, the cardiac parenchyma, the lungs, the liver et cetera, but all white, mucilaginous and flaccid structures not endowed with any solidity. «Also the veins coming from the heart are already joined to the navel. From the navel a vein is coming, directed to the membrane by which the yolk is contained, which in this moment is more liquid and looser than it usually is according to its nature. The other vein is directed to the membrane by which is contained both the whole membrane surrounding the fetus (that is, the tunic of the colliquation) and the yolk as well as the interposed liquid. In fact while the chick slowly grows, a part of the yolk is located aloft and a part down, while the liquid albumen is located in the middle. But under that lower part of the yolk also some albumen exists, likewise also before it was existing under.» Until here Aristotle.

Venas autem iam perspicue videre est arterias comitari; tam has, quae ad albumina tendunt; quam illas, quae vitellum. Vitellus etiam hoc tempore liquescit et fusior est; non totus quidem, sed is qui supernatat, ut pridem diximus; neque etiam venarum ramuli in totum vitellum excurrunt; sed in partem illam duntaxat, quam liquatae cerae instar fusam diximus. Similiter venae, quae ad albumen tendunt, arterias sibi comites habent. Ipsaque albuminis maior pars in humorem candidum, colliquamentum scilicet, abit, qui pullum innatantem amplectitur; interiacetque utramque vitelli portionem, superiorem nempe inferiorem; cui in imo (angulo nempe acuto) pars albuminis crassior et viscidior subiacet. Vitelli pars superior, liquidior iam et fusior apparet, quam inferior; quocunque enim venarum fibrae diffunduntur, partes illae subito intumescunt et liquidiores fiunt.

It is already possible to clearly see the veins keeping company with the arteries, both these going toward the albumens and those going toward the yolk. In this moment also the yolk liquefies and is more melted, however not whole, but what is floating, as I previously told, and neither the little veins flow through the whole yolk, but only in that part I said to be melted as liquid wax. Likewise the veins going toward the albumen have the arteries as their companions. And the same best part of the albumen turns into a candid liquid, that is, the colliquation, which embraces the there floating chick, and is interposed to both parts of the yolk, that is the superior and the inferior one, under whose bottom (that is, at the acute side) the denser and clammy part of albumen lies. The superior part of the yolk appears by now more liquid and looser than the inferior one; in fact everywhere the venous fibres are spreading, those parts immediately swell out and become more liquid.

Decimo vero die, inquit, albumen subsidit, exiguum iam, viscidum, crassum, et subluteum. Quod nimirum in colliquamentum non abiit.

He says: «But at the tenth day the albumen lowers, already scarce, clammy, dense and yellowish.» Which exactly is not turned into colliquation.

Iam maxima albuminis pars in colliquamentum, indeque in foetum absumpta est; totum nempe albumen tenuius; crassiorisque pars maior. Vitellus autem amplior, quam initio erat, conspicitur. Unde manifeste constat, vitellum nondum nutritioni inservire, sed postea huic officio dicatum esse. Et, quantum ex venarum ductu ac distributione coniectura consequi potui, foetus ab initio statim ex colliquamento nutritur; quippe in [273] ipsum duntaxat venae primum disseminantur; deinde in tenuioris albuminis membranam; posteaque in crassius albumen, et vitellum. Similiter et crassius mox albumen pro nutricatu est; ultimoque tandem vitellus.

By now the largest part of the albumen went in the colliquation and hence in the fetus, that is, the whole thinner albumen and the greater part of the thicker one. The yolk appears more wide than at the beginning. Therefore it clearly results that the yolk doesn't serve for the nutrition yet, but that it is destined to this task later. And, as far as I have been able to understand by conjecture from the running and from the distribution of the veins, the fetus since the beginning is at once fed by the colliquation, being that initially the veins are disseminated only in it, then in the membrane of the thinner albumen, and afterwards in the thicker albumen and in the yolk. In the same way also the thicker albumen serves at once as nourishment, and finally the yolk does this for last.

Ita nempe tenerrimus foetus, dum adhuc vermiculus est, tenuissimo optimeque cocto victu alitur; colliquamento, inquam, et albumine tenuiore. Postquam autem adolevit, cibo utitur aetati viribusque suis consentaneo.

So exactly the young fetus, when still is a little worm, feeds on a very thin food and very well digested; that is, with the colliquation and with the thinner albumen. But after having grown it uses a food suitable for its age and its strengths.

Proximis verbis Aristoteles singulorum in ovo situm describit: Prima postremaque parte membrana ovi sub cortice, non corticis membrana sed sub ea; atque in hac liquor inest candidus (colliquamentum scilicet): deinde pullus et eum continens membrana; atque ita separans, ut ne in liquore illo sit foetus ipse.

With the following words Aristotle describes the arrangement in the egg of the single structures: «In the initial and final part the membrane of the egg is located under the shell, not the membrane of the shell but that laying under it, and in this a candid liquid (that is the colliquation) is present: then the chick and the membrane containing it; and separating in such a way that the fetus itself is not located inside that liquid.»

Ubi mendum in textu esse suspicor. Nam, ut res ipsa indicat, ita potius dicendum foret: deinde pullus membrana obvolutus, in eo candido liquore manet sive natat: quae quidem membrana, non est exterior illa totam testam immediate succingens, sed altera huic subiecta; quae, absumpto iam primo albumine exteriore, reliquoque albumine crasso in acutum angulum depresso, ex duabus membranis (nimirum albuminis tenuioris, et colliquamenti propria), una tunica sit, quae tanquam secundina[2] chorion dicta, iam apparere incipit. Apteque ait Aristoteles, liquor in ea candidus inest; quibus verbis, albumen non intelligit, sed factum ex albumine colliquamentum, in quo foetus natat; albumen enim, quod superest, in acutum angulum subsidit.

Where I suspect an error exists in the text. In fact, as the subject itself points out, on the contrary we had to say in the following way: «then the chick, wound by the membrane, remains in that candid liquid, that is, it floats»; but this membrane is not the external one directly surrounding the whole shell, but the other laying under it, which, when by now the first external albumen has been consumed and the remaining thick albumen moved in the acute angle, it is a single tunic composed by two membranes (that is, that of the thinner albumen and that proper of the colliquation), which, also called secundine of the chorion, already starts to appear. Aristotle exactly says «at its inside a candid liquid is found», and with these words he doesn't point out the albumen, but the colliquation derived from the albumen in which the fetus floats; in fact the remaining albumen moves toward the acute angle.