[217] EXERCITATIO UNDECIMA.
De ovi cortice.

11th exercise
The eggshell

TEMPESTIVUM est, post declaratam ovi generationem, de eius partibus, et differentiis agere. Componitur autem ovum, inquit Fabricius[1], ex vitello, albumine, chalazis duabus, tribus membranis (videlicet, una vitelli propria, duabus totius ovi communibus), et demum cortice. Quibus duo addenda sunt, quae vere ovi partibus annumerari non possunt; alterum est, quaedam exigua cavitas in obtusiore ovi parte intus prope putamen efformata; alterum, perexiguum albumque vestigium, quasi rotunda cicatricula vitelli superficiei adnata. Quorum omnium historia exactius nobis afferenda est, ab externis exordientibus. Ovi exterius operculum (quod cortex et putamen appellatur a Plinio; ovi testa, a Quinto Sereno) est integumentum durum, tenue, friabile, porosum, colore vario; nimirum candido, pallido, rubro, maculato, et punctis distincto: videlicet gallinarum et columbarum, candido; palustrium, pallido; tinnunculi, rubro, ut minium; phasianorum, maculato, punctisque distincto, ut ait Aristoteles[2]. Putamen non omnia ova sortita sunt: [218] Etenim serpentium ova eo destituuntur; et gallinae aliquot solent, raro tamen, sine cortice ovum parere. Putamen hoc quanquam durum est, non tamen aequaliter in omnibus partibus durum apparet; sed durius ad ovi principium et superiorem partem est. Ideoque Fabricius[3] dubitandum ait, ex qua materia, et quo tempore, ovi testa gignatur. Aristoteles[4] enim et Plinius[5] affirmant, corticem non intus gigni, sed cum ovum editum est; et prout exit, ita ab aere externo obdurari, calore externo evaporante humorem. Idque factum, ait Aristoteles[6] ne parenti dolorem moveret, et facilius egrederetur. Quemadmodum ovum, aceto emollitum, in vas stricti orificii facile intrudi dicitur.

After having related the generation of the egg, it is the moment of dealing with its parts and its differences. Fabrizi* says: «The egg is composed by yolk, albumen, two chalazae, three membranes (that is, one belonging to the yolk and two in common to the whole egg), and finally by the shell. To these things we have to add two, which cannot be correctly included in the parts constituting the egg: one consists in a small cavity, in correspondence of the obtuse part of the egg, formed inside in proximity of the shell, the other one is a very little and white structure similar to a small round cicatrix which took shape on the surface of the yolk. Of all these structures I must give a more accurate description, starting from the external ones. The most external covering of the egg - the shell (which is called cortex and putamen by Pliny*, ovi testa by Quintus Serenus Sammonicus*) is a hard, thin, friable, porous covering, of varying colour, that is, white, yellowish, red, mottled and punctuated. And precisely, white that of hens and doves, yellowish that of marsh birds, reddish as the minium that of the kestrel*, spotted and speckled that of the pheasants» as Aristotle says. «Not all the eggs are endowed with shell. In fact the eggs of the snakes are lacking it and some hens usually lay an egg without shell, though rarely. Although this shell is hard, nevertheless it doesn't appear equally hard in all the points, but it is harder near the point where the egg begins and in the superior part.» And therefore Fabrizi says that we have to doubt about from what material and when the shell of the egg is produced. In fact Aristotle and Pliny affirm that «the shell is not internally produced, but when the egg has been laid; and as soon as it goes out is hardened by the external air since the external heat makes the damp to evaporate.» And this happens, Aristotle says, «to not provoke pain to the mother and to go out more easily.» Likewise it is said that an egg softened in the vinegar is easily introduced in a vase endowed with a narrow orifice.

Fabricius quidem huic opinioni diu adversabatur; quod ovum duro cortice obductum intus reperisset; idemque mulieres quotidie experiantur, dum extra abdomen digitis ovi duritiem pertentant, ut cognoscant, an gallina mox sit editura ovum, necne. Postea autem, cum accepisset a mulieribus fide dignis, ovorum corticem in exitu ab aere obdurari, qui lentum quendam humorem exeunti ovo circumfusum e vestigio exsiccet, et cortici nondum exacte duro apponat, et induret; atque ipse tandem experientia id comprobasset: mutavit sententiam, putavitque ovum cortice obductum, et constitutionem inter molle et durum adeptum, iam in exitu statim impensius obdurari; concrescente circa putamen e vestigio, propter humoris evaporationem, ut ait Aristoteles, viscosa at tenaci quadam humiditate; cum qua madescens in tota superficie ovum nascitur, et recenti cortici adhaerescens exsiccatur obduraturque, frigido ambiente nonnihil interea conferente. Id quod facile intueberis, inquit, si gallinam domesticam domi habueris, et ovum ei in exitu dextre manu arripueris.

In fact Fabrizi was opposing quite a lot this point of view, «since internally he had found an egg covered by a hard shell, and the women are daily experiencing the same thing when from outside the abdomen they examine with the fingers the hardness of the egg, with the purpose to know if soon the hen is about to lay an egg or not.» But subsequently «having known from reliable women that, when going out, the shell of the egg is hardened by the air, which immediately would dry a certain viscous damp winding the coming out egg and places itself above the not yet correctly hard shell and does it to harden, and finally having experimented this by himself» he changed opinion and thought that «an egg wrapped by the shell, and endowed with a consistency between soft and hard, when goes out immediately hardens quite a lot, because of the immediate thickening around the shell, because of the evaporation of the liquid, as Aristotle says, of a certain viscous and compact dampness, with which the egg soaked on the whole surface is born, and it dries by sticking to the recent shell and hardens, while the cold environment is rather useful. And you will easily observe this (he says) if at home you will have a domestic hen and with ability you will steal by the hand the egg while is going out.»

In hac Aristotelis sententia diu haeseram, donec me certa experientia contrarium docuit. Quippe compertum habeo, [219] ovum in utero, fere semper duro cortice obductum esse. Et aliquando vidi ovum, e gallina viva exemptum, atque etiamnum calens, sine cortice humiditate tenaci madescens; quod tamen ab humiditate illa circa putamen concrescente, aut evaporescente, ut voluit Fabricius, nihil omnino obduruerat, neque ab aere ambiente frigido permutabatur; sed mollitiem, quam in utero habuerat, retinuit.

For a long time I agreed to this affirmation of Aristotle, until a sure experience taught me the contrary. In fact I have ascertained that the egg in the uterus is almost always covered by a hard shell. And sometimes I have seen an egg removed from an alive hen, and a still warm egg, which was without shell and soaked by a strong damp. But nothing of that damp condensing or evaporating around the covering was hardened, as Fabrizi affirmed, nor was modified by the cold surrounding air, but preserved the softness possessed in uterus.

Visum est etiam a me ovum e gallina recens prognatum, perfectoque cortice incrustatum, cuticula tamen membranosa, et molli super corticem inducta vestitum; quae membrana ne quidem post ovi ortum concrescebat. Vidi praeterea ovum e gallina natum, undiquaque testa obductum, praeterquam in acuti culminis apice, ubi exigua mollisque quaedam eminentia (qualem forte Aristoteles pro umbilici vestigio habuit) permansit.

Still by me an egg just laid by a hen has been seen and covered by a completed shell, nevertheless covered above the shell by an overlapping membranous and soft cuticle, and this membrane didn't harden nor after the birth of the egg. Moreover I have seen an egg born from a hen, fully  covered with the shell, except that in correspondence of the apex of the acute extremity, where a small and soft prominence continued to be (perhaps that one thought by Aristotle to be a residue of the navel).

Fabricius itaque mihi videtur a vero recessisse: neque enim ea dexteritate unquam fui, ut ovum in ipso exitu arripere, idque inter molle et durum reperire potuerim. Et hoc fidenter assero, corticem intus sive in utero, ex materia ibidem oblata confici; et non aliter quam reliquas ovi partes, a formatrice eius facultate plasmari; eoque magis, quod viderim, ovum perexiguum (Fabricius centeninum vocat, et nostrates mulieres gallo adscribunt) crusta tectum, intra aliud gallinae ovum maius, perfectum, et cortice circumcirca obductum contineri. Ovum hoc serenissimo regi Carolo[7], domino meo clementissimo, multis aliis coram spectandum praebui. Eodemque anno in limone maiore dissecto, limonem alterum perfectum, sed perexiguum, flavo cortice obductum reperi. Quod iam crebro in Italia contingere audio.

Insofar it seems to me that Fabrizi strayed from the truth, and in fact never I had such a skill to be able to capture an egg while is going out and to find it between soft and hard. I also resolutely affirm what follows: the covering is internally made, that is, in the uterus, starting from material put available still in the same place, and that is moulded in a way not different than the remaining parts of the egg by the maker power of the uterus. All the more so because I have seen a very small egg (Fabrizi calls it centesimo - hundredth - and our women attribute it to the cock) covered by a crust, to be contained inside another greater egg of hen, completed and covered all around by the shell. I offered this egg to the Serene King Charles I my very clement lord, to be observed at the presence of a lot of other people. In the same year in a sectioned greater lemon I found another completed lemon, but very small, covered by a yellow peel. I hear that by now this frequently happens in Italy.

Communis eorum error est, qui hodie philosophantur, quaerere varietatis partium causas, ex diversa materia unde oriantur. Ita medici, varias corporis partes, ex diversa materia, vel sanguinis, vel spermatis, gigni et enutriri asserunt: nempe ex [220] tenuiore materia, partes molles, ut carnem; ex duriore et crassiore, terrestres partes, ut ossa et caetera. Nos autem errorem hunc, nimis pervulgatum, alibi refutavimus. Nec minus illi falluntur, qui ex atomis omnia componunt, ut Democritus; aut ex elementis, ut Empedocles. Quasi generatio nil aliud foret, quam separatio, aut congregatio, aut dispositio rerum. Non est quidem negandum, ut aliquid ex aliquo producatur, haec quae dicta sunt necessario requiri; generatio tamen ipsa ab iis omnibus diversa est. In hac sententia Aristotelem reperio: atque ipsemet postea docebo, ex eodem albumine (quod omnes fatentur similare esse, non autem ex diversis partibus compositum) singulas pulli partes, ossa, ungues, plumas, carnem, caeterasque omnes procreari et nutriri. Praeterea, qui hoc modo philosophantes materialem duntaxat causam assignant, et vel ex elementis sponte aut casu concurrentibus, vel ex atomis varie dispositis, causas rerum naturalium deducunt; quod est in operibus naturae, atque in generatione et nutritione animalium praecipuum, haud attingunt: divinum nempe illud efficiens, et naturae numen (quod summa arte, providentia, et sapientia operatur, omniaque in finem aliquem, sive boni alicuius gratia efficit) non agnoscunt; sed divino architecto honorem derogant, qui non minore artificio et providentia corticem, in ovi tutelam, exstruxit; quam caeteras omnes ovi particulas, ex eadem materia, et per eandem facultatem formatricem composuit.

A common error of those people today posing as philosophers is to investigate whence originate the causes of the variability of the parts composed by different material. So the physicians affirm that the various parts of the body are produced and fed by different material, either of the blood, or of the sperm; and precisely, by a slimmer material the soft parts as the flesh, by a harder and denser material the terrestrial parts as the bones et cetera. But in a point I refused this too much diffused error. And those people composing all the things on the basis of the atoms as Democritus*, or from the first elements as Empedocles*, are not less wrong. As if the generation is nothing but a separation or a congregation or an arrangement of the things. But we don't have to deny, in order that something produces itself from something, that necessarily these said things are required. Nevertheless the generation itself is different from all such things. In this affirmation I discover Aristotle and subsequently I myself will show that the single parts of the chick, bones, toenails, feathers, flesh and all other parts are produced and feed starting from the albumen itself (which all people acknowledge to be identical, not composed by different parts). Besides, those people posing as philosophers in this way only attribute a material cause, and they deduce the causes of the natural things either from the elements concurring spontaneously or by chance, or from the atoms placed in various manners, they don't reach at all what is fundamental in the works of nature and in generation and nutrition of the animals. Being just working the divine one, they don't admit also the god of the nature (who acts with great skill, foresight and wisdom, and brings all the things to some term, that is, for some advantage). But they remove the honor from the divine architect who has built the shell as guardianship of the egg, with an art and with a foresight not inferior to that employed in building all the other small parts of the egg, starting from the same material and through the same maker ability.

Quanquam illa, quae iam diximus, vera sunt, ovum scilicet, etiamnum in utero exsistens, duro cortice muniri; tantopere tamen apud me semper valuit Aristotelis auctoritas, ut non temere ab illa recedendum putem; ideoque credam, quod etiam observationes meae confirmant, huic corticis concretioni, aliquid in ipso eius exitu ab ambiente aere accedere; lentumque illum et lubricum humorem, a quo dum nascitur madet, statim ab eius exclusione indurari. Cortex enim, dum in utero [221] est, multo tenuior, et transparens magis, ac laevi superficie conspicitur; edito autem iam ovo, crassior multo, minus translucidus, et superficie aspera (tanquam polline albissimo adsperso, et nuper accrescente) apparet.

Even if those things we have just said are true, that is, that the egg, when still in the uterus, is endowed with a hard shell, nevertheless for me the authority of Aristotle always had such a great value to not think to stand back of it without reason; and therefore I would believe, since also my observations confirm it, that to this concretion of the shell something is added from the ambient air in the same moment of its release, and that that viscous and slippery humor, by which it is wet while coming out, immediately is hardened by its release. In fact the shell, while in uterus, appears very thinner and more transparent, as well as endowed with a smooth surface; but when the egg by then has been laid, it appears more thick, less transparent and with a rough surface (as if dust of very white flour had been sprinkled and is adding since little time).

Liceat nobis, hic dum sumus, aliquantulum exspatiari.

While we are treating this matter we have to be allowed to linger a little bit.

In Scotiae insulis orientalibus desertis, tanta omnis fere generis avium marinarum copia reperitur; ut, si, quae a fide dignis accepi, retulero, verear, ne fabulas maiores narrare videar, quam quas auctores varii, de anseribus Scoticis ex arborum quarundam fructibus, quos nunquam viderunt, in mare delabentibus, prognatis, tradiderunt. Quae ipsemet vidi, bona fide edisseram.

In the oriental desert islands of Scotland such a great abundance of almost every type of sea birds is found that, if I will report what I learned from trustworthy people, I fear to seem that I narrate some fables greater than those various authors handed down about Scottish geese born from the fruits of certain trees that they never had seen and falling into sea. What I myself have seen I will tell bona fide in particular.

Est insula parva, Scoti Basse [8] nominant (ex hac una, lector, nosce omnes), non procul a littore in alto mari sita, abrupto et confragoso clivo editissima (verius saxum ingens sive scopulum dixeris); haud amplius mille passuum circuitu amplitudo eius clauditur. Huius insulae superficies, mensibus Maio et Iunio, nidis, ovis, pullisque propemodum tota instrata est; adeo ut vix uspiam, prae eorum copia, pedem libere ponere liceat: tantaque supervolitantium turba, ut, nubium instar, solem coelumque auferant; tantusque vociferantium clangor et strepitus, ut prope alloquentes vix audias. Si subiectum mare, inde (tanquam ex edita turri et altissimo praecipitio) despexeris; idem quoquoversum infinitis diversorum generum avibus natantibus, praedaeque inhiantibus opertum videas. Quemadmodum, verno tempore, stagna alicubi ranis refertissima cernuntur: et aprici colles montesque acclives frequentissimis ovium caprarumque gregibus obsessi eminus spectantur. Si circumnavigando imminentem clivum suspicere libuerit, videas in singulis praerupti loci crepidinibus et recessibus, avium cuiuslibet generis et magnitudinis ordines innumerabiles; plures sane, quam illuni nocte sereno coelo stellae conspiciuntur: si advolantes, avolantesque eminus adspexeris, apum profecto ingens examen credas. [222] Haud facile dixerim, quantus reditus quotannis ex plumis, et nidorum foco utilium reliquis, ovorumque coctorum commercio possessori accedat: adeo, quod ipse mihi narravit, fidem exsuperat. Hoc unum, quod ad propositum nostrum propius spectat, potissimum mihi memorabile videtur; estque praefatae multitudinis clarum indicium. Tota haec insula adventantibus candido nitore micat; clivique, tanquam ex albissima creta, fulgent; saxi tamen nativus color obscurus, et niger est. Insulam albam et splendentem reddit crusta ei adhaerens albissima, friabilis, eiusdemque cum ovi cortice consistentiae, coloris, et naturae: adeo omnia eius latera integumento duro, testaque alba friabili superinducta, trullissata sunt. Pars ima, quam reciproca maris unda quotidie abluit, nativo suo colore conspicua, luculenter docet, albedinem illam in summo fucatam esse, et a liquidis avium excrementis, quae cum alvi faecibus elidunt, proficisci; quibus, tanquam ovi testa alba, dura, et friabili, saxum obtegunt et (accedente aeris ambientis frigore) incrustant: eodemque modo, Aristoteles quoque, et Plinius, ovi testam fieri voluerunt. Harum avium nullae illius loci inquilini sunt; sed pariendi causa advenae, per aliquot duntaxat septimanas ibidem, tanquam in diversorio, morantur; donec scilicet pulli una avolare possint. Tamen alba illa crusta adeo solida, firma, et profunda adhaeret, ut genuinam illius soli naturam crederes.

There is a small island called Basse by Scots - today The Bass - (only on the basis of this, o reader, know all of them) located on the open sea not far from the coast, very high because of a steep and stony slant (you could call it more exactly a big rock or cliff), and its ampleness is delimited by a circumference of no more than a thousand paces - 1 Roman mile, equal to 1.48 km. The surface of this island in the months of May and June is almost entirely covered by nests, eggs and chicks, to such a point that, because of their abundance, it is hardly possible to freely put a foot in some point, and so much is the crowd of the birds flying aloft that they steal the sun and the sky as if being clouds, and so much is the cackle and the clash of shouting ones that barely you succeed in hearing those people speaking nearby you. If from here you will succeed in seeing from above the underlying sea (as from an elevated tower and from a tall precipice), likewise in whatever direction you could see the coverage done by endless swimmer birds of different species and avid of a prey. Likewise in spring in some place the ponds full of frogs are seen, and in the distance the sunny hills and the steep mountains are seen occupied by very numerous flocks of sheep and goats. If you will like to look at an impending slope during the circumnavigation, you could see in the single cliffs and in the recesses of a steep place the innumerable crowds of birds of whatever type and size, certainly more numerous than the stars seen in a serene sky during a night without moon. If you will see in distance that they fly toward you and that fly away, you have to believe that certainly it is a great swarm of bees. I could not easily affirm at all how much money annually enters the hands of the owner, coming from the feathers, from the other things of the nests useful to the fire and from the commerce of the cooked eggs: insomuch that what he himself told me goes beyond the credibility. Only this thing, which more nearly concerns our purpose, seems me above all worthy to be remembered and it is a clear proof of the above-mentioned crowd. This whole island, for those are coming here, blazes of a candid shine and the slants are resplendent as if made of very white clay; nevertheless the original colour of the rock is dark and black. The sticking encrustation makes the island white and shining, the encrustation is white, friable and of the same consistence, colour and nature as the shell of the egg: to such a point all its sides have been plastered by a hard covering and by an overlapped friable white shell. The lowest part, daily washed by the coming and going wave of the sea, well visible for its original colour, abundantly shows that such whiteness in the high part is artificial and that originates from the liquid excrements of the birds they expel with the faeces of the belly, by which they cover the rock as being a white, hard and friable eggshell, and they crust it (when the cold of the ambient air comes). Also Aristotle and Pliny established that the shell of the egg is formed in the same manner. None of these birds is an inhabitant of this place, but they are migrants because of reproduction reasons, and they dwell here only for some weeks as being a housing, obviously until when the chicks are not able to fly away together. Nevertheless that white crust sticks in a so solid, resistant and deep manner that you would believe it a natural characteristic of that ground.

Excrementum hoc liquidum, album, et lucidum, ex avium renibus cum urina per ureteres in communem cavitatem seu cloacam delabitur[9]; faeces alvi ibidem cooperit, atque una prodit foras: estque crassior earum urinae pars, quam in nostra sedimentum sive hypostasin nominamus. Nonnulla de hac re supra diximus, atque eandem alibi plenius demonstravimus. Albi huius excrementi copia ibi praesertim conspicua est, ubi accipitres stationibus suis conterminos muros faecibus illinunt, albedine gypsea obducunt, et quasi cerussa depingunt.

This liquid, white and shining excrement goes down from the kidneys of the birds together with the urine through the ureters in the common cavity or cloaca. Still here it covers the faeces of the belly and together with them it comes out, and the part of their urine, that in our one we call sediment or hypostasis, is rather dense. Before I said some things about this material and in a point I treated it in a rather complete way. A great abundance of this white excrement exists above all there where the hawks* sprinkle the walls confining with their houses with the faeces, they cover them with a whiteness similar to chalk and paint them as if using a white lead.

[223] In struthionis mortui cloaca, gypsei huius caementi eam copiam reperi, quae manum integram facile impleret. Similiter in testudine terrestri, caeterisque quadrupedibus oviparis, album hoc caementum abundat; forasque eiectum, evaporatione tenuioris partis, cito vel in crustam friabilem, aut pollinem ovi testae pulveratae simillimum, concrescit.

In the cloaca of a dead ostrich I found such an abundance of this chalky cement to easily fill a whole hand. Likewise this white cement is abundant in the terrestrial turtle and in the other oviparous quadrupeds, and after it has been issued outside, because of evaporation of the less dense part it quickly solidifies either in a friable crust or in a dust very similar to the pulverized shell of the egg.

Inter avium tam diversa genera, quae ad insulam dictam generandi causa advolant, tamque varios nidorum modos, in quibus ova incubant; una mihi monstratur avis, quae ovum duntaxat singulare sive unicum parit, idemque super cuiusdam lapidis acuti fastigium collocat (nullo nido, aut conquisita strue supposita) idque tam firmiter, ut mater abire et redire, salvo ovo, possit. Hoc autem si quis loco dimoveat, nulla arte postea stabiliri potest; quin inde devolutum, praeceps in mare ruat. Locus nempe, ut dixi, caemento albo incrustatur; ovumque, cum nascitur, lenta et viscosa madet humiditate, qua cito concrescente, tanquam ferrumine quodam, substrato saxo agglutinatur.

Among the so different species of birds reaching by flight the aforesaid island for reproductive reasons, and among so many different types of nests in which they brood the eggs, a bird is shown me laying a single or only one egg and puts it on the summit of a sharp stone (without any nest or an underlying amassed pile) and this is prepared with so many certainty that the mother can go and come and the egg remains safe. But if someone moved its position, subsequently it cannot be made stable with any device, and actually, having been moved from such position, it quickly falls in the sea. As I just said, the place is crusted by white cement, and the egg, when is born, is wet by a sticky and viscous damp, by which, since quickly solidifies as being a glue, it is stuck to the underlying rock.

Tam subitae concretionis exemplum apud statuarios videre est, qui ex alabastro calcinato vel gypso aqua temperato, caementum liquidum efficiunt; quo ita applicito, defunctorum vultus, vel alterius cuiuslibet rei, etiam minutissimae, simulacrum et imaginem excipiunt; eodemque mox indurescente, proplasmata concinnant.

It is possible to see an example of a so quick solidification among the makers of statues, who prepare liquid cement from the alabaster treated with lime or from the plaster mixed with water, and after having treated it so, they draw the portraits of the dead persons or the effigy and the image of any other thing also very small, and they prepare the sketches with the cement which hardens  quickly.

Quemadmodum igitur in omnibus fere liquoribus terreni aliquid inest (exempli gratia, in vino, tartarum; in aquis, limus, aut sabulum; in lixivio, sal; qui, humido magnam partem exhalante, concrescit et subsidit); ita pariter sedimentum album avium, una cum urina, e renibus in cloacam descendere arbitrabar, ovumque ibidem eodem oblini et incrustari; ut pavimenta a falconibus, et praedictae insulae totum clivum gypsari diximus: et perinde atque vasa, locaque alia ubi crebro mingitur, flavo cortice tegi solent; materia illa scilicet concrescente, [224] ex qua calculi in renibus, vesica, aliisque corporis partibus generantur. Credebam, inquam (praesertim Aristotelis et Plinii auctoritate ductus) ex huiusmodi albo sedimento, quod in omnibus oviparis, quorum ova duro cortice integuntur, copiose adest, ovi gallinacei corticem fieri, et ab ambiente frigore dum excluditur concrescere: Eandemque meam sententiam aliae quoque plurimae observationes adeo confirmarunt; ut vix mihi temperem, quin credam, aliquam saltem testae partem inde produci.

Therefore as something earthy is present in almost all the liquids (for example, the tartar in wine, the slime or the sand in waters, in lye the salt which, when the damp exhales in a large extent, hardens and decreases), the same I thought that the white sediment of the birds went down together with the urine from the kidneys in the cloaca and that still here the egg was dressed and covered by it, likewise I said that the floors are covered of plaster by the hawks as well as the whole slope of the above-mentioned island is covered. And in the same manner also the chamber pots, and the other places where often we urinate, usually cover themselves of a yellow layer, obviously because of the thickening of that matter by which the calculi are produced in kidneys, in urinary bladder and in other parts of the body. I add that I believed (above all induced by the authority of Aristotle and Pliny) that from such a white sediment, which is abundantly present in all the oviparous animals whose eggs are covered by a hard shell, the shell of hen's egg was formed, and that when laid it was hardened by the surrounding cold. And also other numerous observations confirmed my same affirmation to such a point that hardly I could refrain from believing that at least some part of the shell is produced in this manner.

Veruntamen, ut recte monet Fabricius, ratio omnis conticescat oportet, ubi experientia refragatur. Vitiumque huius seculi est nimis familiare; phantasmata, ex coniectura, levique ratiocinio (sine oculorum testimonio) nata, pro manifesta veritate obtrudere.

Nevertheless, as rightly Fabrizi recommends, «it is worthwhile that any reasoning keeps silent when the experience is opposing». And the vice of this century is too much commune: to impose the fantasies born from a hypothesis or from a superficial reasoning (without visual testimony) as if they were an evident truth.

Mihi enim certo compertum est, ovum, saltem apud nos, in ipso utero exsistens cortice integi: licet Aristoteles et Plinius contrarium affirment, idque Fabricius quoque haud pertinaciter negandum putet. Forsitan locis calidioribus, et robustioribus gallinis, ovum molle et sine testa ut plurimum nascitur; apud nos vero id rarissime contigit. Ita mihi olim, Venetiis cum essem, aromatarius medicus clarissimus ostendit, inter utramque faseoli laminam, minutum folium efformatum; cum tamen apud nos, in similibus faseolis, duntaxat apex parvulus nascituri germinis appareat. Tantopere ad foecunditatem et celeriorem proventum, coeli, soli, aerisque benignus tepor et clementia conducunt.

In fact I verified with certainty that the egg, at least among us, when located in the uterus is covered by the shell, although Aristotle and Pliny affirm the contrary, and also Fabrizi thinks that this must not be denied with stubbornness. Perhaps in warmer localities and in more strong hens, the egg mostly is born soft and without shell, but among us this happens very seldom. So once, while I was in Venice, a very famous pharmacist showed me a small leaf developed among the two valves of a bean, while among us in such beans only appears a small apex of the gem about to be born. To such a point the mild warmth and the mildness of sky, ground and air bring to fertility and to a swifter growth.