[215] EXERCITATIO DECIMA.
De ovi incremento, et exitu.

10th exercise
The increase of the egg and its coming out

AUDIAMUS Fabricium: Sicuti dicimus, inquit[1], ventriculi actionem esse chylificationem; et testium actionem, seminis generationem; quia in ventriculo chylus, in testibus semen comperiatur: sic ovorum generationem esse pennatorum uteri actionem omnino asseveramus, quod ovum inibi inveniatur. Sed non est haec sola uterorum functio, ut patet; sed ea quoque adnotatur et enumeratur, nimirum ovi augmentum, quod ovo statim genito succedit, quousque perfectum efficiatur et iustam magnitudinem adipiscatur. Etenim gallina non prius naturaliter ovum parit, quam perfectum factum et congruam magnitudinem adeptum fuerit. Igitur uterorum actio, tum ovi generatio, tum augmentum est: augmentum autem nutritionem supponit et includit. Sed cum generatio omnis a duobus perficiatur, videlicet opifice, et materia; agens, in ovorum procreatione, nil aliud est quam instrumenta seu organa proposita, nimirum duplex uterus: materia vero, nulla alia quam sanguis.

We have to hear Fabrizi* who says: «In fact, as we say that the activity of the stomach is the production of the chyle* - today chyme* - and that the activity of the testicles is the generation of the semen, since chyle is found in the stomach and semen in the testicles, so we are quite guarantors of the fact that the activity of the uterus of birds consists in the generation of the eggs, since just there the egg is found. However the function of the uteri is not only this, as it is clear, but is also observed and numbered above all that of the growth of the egg immediately following the produced egg until became perfect and acquired the correct size. In fact the hen doesn't lay the egg in a natural way before it has been completed and it acquired a correct dimension. Insofar the activity of the uteri consists both in the generation of the egg and in its growth, and the growth presupposes and implicates a nutrition. But since each generation is ended by two agents, that is by the creator and by the matter, in the generation of the eggs the performer consists in the described tools, or organs, that is, the two uteri, while the matter is constituted only by the blood.»

Nos autem brevitati studentes, omissis, ut oportet, altercationibus, ut facile concedimus uteri officium et usum procreandis ovis destinatum esse; ita efficiens adaequatum, ut dici solet, et immediatum, in ovo ipso contineri asseveramus; ovumque, non ab utero, sed ab interno principio naturali sibique proprio, tum generari tum augeri censemus; principium hoc a tota gallina primum vitellum inchoatum, primamve papulam profluere; quod deinde, ceu innatus calor aut natura opifex, vitello inhaerens, ipsum nutrit, augetque: quemadmodum in unaquaque corporis parte facultas quaedam inest, qua ipsae singillatim aluntur et crescunt.

But we, who are trying to be brief, after having left aside the disputes, as it is suitable, like easily we grant that the task and the employment of the uterus is destined to the generation of the eggs, so we affirm that in the egg itself the suitable efficient cause is contained, as usually it is said, and immediate, and we believe that the egg is generated and increased not by the uterus, but by a natural inner principle and peculiar to it, that this principle springs from the whole hen that gave beginning to the first yolk or to the first vesicle, which subsequently, being maker the innate heat or the nature, remaining linked to the yolk, nourishes and increases it. Likewise a certain power is present in any part of the body, thanks to which the parts are singly fed and grow.

[216] Modum autem quod attinet, quo vitellus albumine augetur, Aristoteles[2] videtur credidisse, in ovis, dum mollibus membranis obvolvuntur, canalem umbilicalem in acuta ovi parte esse (ubi ovi principium statuit), per quem augeatur. Quam sententiam Fabricius[3] reprehendit, negatque ullum talem canalem adesse, aut vitellum ullibi utero adhaerere: atque dubium de eiecti ovi appendicula diluit; dicendo, ovum augeri dupliciter, prout duplex est uterus, superior et inferior; et ovi substantia duplex, vitellus et albumen. Vitellus adaugetur vero augmento, sanguine nempe, qui ad ipsum per venas porrigitur, dum adhuc vitellario appenditur. Albumen autem alio modo adaugetur et accrescit ac vitellus: etenim non per venas, neque per nutritionem, ut vitellus, incrementum suscipit; sed per iuxtapositionem vitello, dum per secundum uterum devolvitur, adhaerescit.

About how the yolk is increased by the albumen, it seems that Aristotle believed that «in the eggs, while are wound by the soft membranes, in the acute side of the egg there is an umbilical channel» (where he stated the principle of the egg) «through which the yolk would be increased.» Fabrizi criticizes this affirmation and denies that «a similar channel exists, or that the yolk in some point sticks to the uterus.» And he clarifies the doubt about the appendix of the laid egg by saying that «the egg grows in two manners, since the uterus is double, superior and inferior, and the substance of the egg is double, the yolk and the albumen. The yolk grows for a true increase, just thanks to the blood brought to it through the veins while it is still hung to the ovary. On the contrary the albumen grows in another way and grows as the yolk: in fact it doesn't acquire an increase through the veins and neither through a nutrition as the yolk, but it sticks for juxtaposition to the yolk while going down through the second uterus.»

Mea autem sententia, ovum ubique eodem modo augetur, quo vitellus in racemo; a principio nempe intrinseco concoquente: hoc solum discrimine, quod in racemo alimentum illi per vasa deferatur, in utero autem iam paratum inveniat quod imbibat. Quippe in omni nutritione et accretione, aequaliter necessaria est partium iuxtapositio, et applicati alimenti concoctio ac distributio: neque haec minus, quam illa, vera nutritio censenda est: siquidem utraque novi alimenti accessu, appositione, agglutinatione, atque transmutatione contingit. Nec minus sane ciceres vel fabae, attracto per tunicas suas terrae humore, quem veluti spongiae imbibunt, vere nutriri dicuntur; quam si eundem per venarum oscula admitterent: et arbores corticibus suis rorem pluviasque absorbentes, aeque vere aluntur ac per radices solent. Verum de nutritionis modo, alibi plura annotavimus. Impraesentiarum nos alia difficultas tenet; nimirum an vitellus, dum albumen acquirit, separationem eius aliquam et distinctionem non faciat; atque ita, dum augetur, [217] pars quaedam terrestrior in vitellum seu medium ovi, tanquam ad centrum, ut Aristoteles voluit, subsidat; pars alia levior eundem circumambiat. Inter vitellum enim, qui adhuc in racemo est, et eum qui in medio perfecti ovi reperitur, hoc maxime interest; quod ille, quamvis luteo colore sit, consistentia tamen magis albumen referat; et coctura, huius instar, crassescat, compactus, viscidus, et in laminas fissilis sit: vitellus vero, qui in ovi perfecti medio est, a coctione friabilis fiat, et consistentiae magis terrestris (non crassae, et glutinosae, albuminis instar), appareat.

In my opinion the egg becomes larger anywhere in the same manner the yolk is growing in the ovary, that is, from an intrinsic digesting principle; only with this difference, that in the ovary the food is brought to it through the blood vessels, while in the uterus it finds already prepared what is absorbing. Therefore in every nutrition and growth is equally necessary the juxtaposition of the parts and the digestion as well as the distribution of the applied food, and this nutrition must not be judged less true than that one: since both happen for arrival, apposition, agglutination and transformation of a new food. In truth it is neither said that the chickpeas or the broad beans are truly fed by the earth's liquid attracted through their tunics and which they absorb as sponges, as if they introduce it through small openings of the veins, and the trees, absorbing through their barks the dew and the rains, are fed as well as it usually happens through the roots. In truth we reported in other points quite a lot of things about the manner of feeding. For the moment another difficulty occupies us, and, that is, if the yolk, while acquiring the albumen, doesn't cause some of its own separation and distinction, and so, while it is growing, some more terrestrial part moves in the yolk or in the middle part of the egg as being the centre, as Aristotle wanted, and another lighter part surrounds it. In fact, between the yolk that is still in the ovary and that found in the centre of the completed egg, what above all interests is the following: the first one, even if yellow in colour, nevertheless for consistence resembles more to the albumen, and with the cooking it condenses like this one becoming compact and viscid, and it becomes divisible in foils; on the contrary the yolk placed in the centre of the completed egg, with the cooking becomes friable and appears of more terrestrial consistence (not thick and gelatinous as the albumen is).