[46] §. 11.
Dies tertius.

§ 11
Third day

Blastoderma increvit, et hemisphaerium vitelli aequat; area vasculosa diametri 70-80 centesimarum[1] est.

The blastoderma is increased and matches the hemisphere of the yolk; the vascular area has a diameter of 70-80 hundredths of inch <– 1.75-2 cms>.

Areae pellucidae forma, hucusque distinctis finibus circumscripta, ex regulari in irregularem longiorem et superne et inferne magis acuminatam mutata est.

The shape of the pellucid area, until this point circumscribed by separate boundaries, from regular changed into irregular, longer and more pointed aloft and downwards.

Loco halonum, qui jam hora 36 evanuerunt, totum blastodermati subjacens vitellum liquefactum est, praecipue tamen proxime sub foetu et sub area vasculosa, materia alba, liquida, lactique[2] simillima continetur.

In place of the halos, faded away at the 36th hour, the whole yolk underlying the blastoderma is liquefied; however, above all very near under the fetus and the vascular area, a white material is contained, liquid and very similar to milk.

Ex illo vasorum reti nunc vasa sanguifera orta sunt, quorum ramis et truncis membrana vasculosa elegantissime ornatur; trunci foetum attingunt, rami minutissimi inter se et cum annulo terminali compinguntur.

From that net of vessels now the blood vessels are born, by whose branches and trunks the vascular membrane adorns itself in a very elegant way; the trunks reach the fetus, some very small branches are joining among themselves and with the terminal ring.

[47] Area vasculosa arteriis[3], venis et sinu gaudet. Arteriarum trunci sub angulo recto ex foetu medio egrediuntur, mox in tres vel quatuor ramos dividuntur; unde permultum ramificantur, et innumerabili multitudine surculorum tum sinum terminalem ineunt, tum cum subtilissimis venarum surculis permultas anastomoses efficiunt[4].

The vascular area enjoys of arteries, veins and of an inlet. The trunks of the arteries go out, at right angle, from the central part of the fetus, at once are subdividing in three or four branches; therefore are branching a lot and with an innumerable multitude of sprigs they not only enter in the terminal sinus, but with very thin venous sprigs also create a lot of anastomoses.

[48] Sanguineus annulus terminalis, {quam} <quem> venam terminalem vocant, licet omni pariete careat, et merus sit sanguinis rivulus blastodermatis stratis retentus et coercitus, hora 30 imperfecte circularis, supra caput foetus cordiformis inflectitur. Ex hoc sinu sanguineo duae vel tres nascuntur venae, ad foetum tendentes, ita dispositae, ut eorum directio axi foetus correspondeat. Harum prima superior, descendens, plerumque duplex, immediata sinus terminalis continuatio est[5]; ex superiore parte versus caput descendit, vaginae capitis incumbit et in regione cardiaca cor adit; si duae adsunt, ante hanc cum corde conjunctionem, brevem truncum formant. Secunda inferior ascendens, ramis minutis ex opposita sinus terminalis regione nata, supra caudam adscendit, et cum descendentibus proxime a corde conjungitur.

The terminal blood ring, called terminal vein, although is devoid of any wall and is a pure rivulet of blood contained and shut in the layers of the blastoderma, defectively circular at the 30th hour, it bends heart shaped above the head of the fetus. From this blood inlet two or three veins going toward the fetus are born, placed in such a way that their direction corresponds to the axis of the fetus. The first of them is superior, descending, mostly duplex, an immediate continuation of the terminal sinus; from the superior part it goes down towards the head, overhangs the wrap of the head and goes near the heart in the cardiac region; if there are two of them, in front of this conjunction with the heart they form a short trunk. The second is inferior, ascending, born from tiny branches from the opposite region of the terminal sinus, goes up the tail and is connected by the very nearby heart with the descendant veins.

Cor in sinistro foetus latere situm, et vagina capitis tectum, (qua remota ejus structuram manifestius perspicies,) consistit ex tribus vesiculis, tribus isthmis conjunctis.

The heart, located in the left side of the fetus and covered by the wrap of the head (which, when removed, you will see better its structure), is made by three vesicles connected by three isthmuses.

[49] Prima harum vesicularum auricula est, secunda ventriculus et tertia aortae bulbus[6].

The first of these vesicles is the atrium, the second the ventricle and the third one the aortic bulb.

Auricula globosa inferne cum venis cohaeret, superne per canalem auricularem transversim ab illa discedentem cum oblongo ventriculo conjungitur. Ventriculus {maxim ea} <maxime a> foetu distat, et qua parte canalem auricularem latissimo suo fine recipit, nodi contorti speciem fert. Ventriculus per gracilius fretum in latiorem aortae bulbum transit[7], unde canalis exiguus gracillimus cylindricus in duas, vel tres, aortae radices desinit.

The atrium, globular, below joins with the veins, above joins with the lengthened ventricle through the auricular channel transversally going down from the atrium. The ventricle is very far from the fetus, and in that point where it receives the auricular channel in its very wide final part, it shows the appearance of a twisted knot. The ventricle, through a rather thin passage, goes in the more wide bulb of aorta, whence a very thin small cylindrical channel goes to end in two or three roots of the aorta.

Aorta magno arcu facto usque ad foveam cardiacam simplicem format truncum, hicque in duos finditur, quorum unusquisque suo in latere vertebras columnae dorsalis tegit et contractus, ad caudam quasi evanescere videtur. Nascuntur ex his arteriis, ultra medium foetum, duae, [50] supra commemoratae, arteriae laterales areae vasculosae[8].

The aorta, after having made a big arc, forms a simple trunk until the cardiac cavity and here it is subdividing into two trunks, each of them covering the vertebrae of the dorsal column at their side and, contracted, it seems almost to fade away in direction of the tail. From these arteries, beyond the half of the fetus, the two previously quoted lateral arteries of the vascular area are born.

[51] Jam qua se habeat circulatio sanguinis ratione, patet. Ex ventriculo sanguis [52] per aortam in duas arterias laterales propellitur; ex minutissimis harum ramificationibus, [53] tum in sinum terminalem, tum in minutissimos venarum surculos transit; [54] inde a venis excipitur et per ascendentem et descendentem cordi advehitur.

Now it is evident why the circulation of the blood is happening. The blood, starting from the ventricle, is pushed through the aorta in two lateral arteries; from their very small ramifications it passes both in the terminal sinus and in very tiny ramifications of the veins; hence it is received by the veins and is brought to the heart through the ascending and descending vein.

Quatuor sunt plagae in sinu terminali commemorandae, {quorum} <quarum> binae sibi oppositae, quoad sanguinis directionem inter se conveniunt, nempe duae laterales et duae alterae capitalis caudalisque. A duabus plagis lateralibus truncis arteriarum e diametro oppositis sanguis, quem sinus ex arteriarum ramis suscipit, utroque versus diffluit, ita ut pars plagam caudalem, pars capitalem petat, quasi in tali plaga adesset punctum, ubi sanguis de [55] itinere eligendo dubius haereat. Sanguinis pars in sinus terminalis quadrante superiore dextro ad venam descendentem dextram, in quadrante superiore sinistro ad venam sinistram pertingit, vena ascendens sanguinem ex utroque quadrante inferiori suscipit. Quem sanguinis motum Cl. Spallanzani ita describit: "Il sangue nelle due arterie si muove a spinte, facendo nella sistole del cuore un tratto di cammino men corto, che nel antecedente sperienza, ma soffermandosi secondo il solito nella diastole, e solo tornando ad andare avanti nella sistole sussequente. Quando va avanti, quella porzione d'impulso, che ha nel tronco, non la sminuisce ne' rami, e nelle ramificazioni, che metton capo nella circonferenza; ma la sminuisce bene all'entrar nell'altre ramificazioni arteriose, che non giungono fino alla circonferenza, anzi innoltrandosi in esse perde ogn'impeto, divitando il suo moto equabile, ma lentissimo. In questi fini arteriosi, e principii venosi si puo dire che sia equabilità di moto nel sangue."

In the terminal sinus there are four spaces to remember, two of them are opposed to each other, until when they make to gather among them the direction of the blood, and precisely two lateral and other two, cephalic and caudal. From the two lateral spaces the blood, that the sinus takes from the branches of the arteries, flows in both directions from the trunks of the arteries opposed to the diameter, so that a part reaches the caudal space and the cephalic space, as if in such space there is a point where the blood is doubtful about the way to choose. Part of the blood in the right superior quadrant of the terminal sinus arrives at the right descending vein, in the left superior quadrant at the left vein, the ascending vein gathers the blood from both the inferior quadrants. The illustrious Lazzaro Spallanzani describes this movement of the blood as follows: "The blood in the two arteries moves with pushes, doing in the systole of the heart a tract of walk less short than in the previous experience, but pausing as usual in the diastole, and only returning to go on at the following systole. When it goes on, that portion of impulse it has in the trunk doesn't diminish it in the branches and in the ramifications ending in the circumference; but diminishes well it when entering in the other arterial ramifications, that don't come until the circumference, or rather, by advancing in them, loses every impetus, its motion becoming uniform, but very slow. In these arterial ends, and venous beginnings, it can be said that there is an uniformity of motion in the blood."

Embryo superiori sua corporis parte, collo incurvo, in sinistrum latus decumbit, [56] et caput ita positum est, ut occiput antrorsum, sinciput versus cor prospiciat, inferiore parte pronus est situs. Usque ad foveam cardiacam a capitis vagina tegitur, inde ad usque caudam patet. Axin embryonis medulla spinalis, plicis primitivis connatis inclusa, constituit; cum adnexis vertebris dorsalibus et {lumbalibus} <lumbaribus> inferiorem partem involucrum caudae tegit.

The embryo, with its superior part of the body, with the bent neck, lies turned toward the left side, and the head is arranged in such a way that the occiput is turned at the front, the sinciput toward the heart, and the position is prone with the inferior part. Until the cardiac fossa it is covered by the wrap of the head, and from this point it is uncovered until the tail. The spinal marrow, held in congenital primitive plicae, constitutes the axis of the embryo; with the attached dorsal and lumbar vertebrae the wrap of the tail covers the inferior part.

In anteriore latere thoracis ventriculus, qui die secundo antrorsum directus erat, nunc oblique deorsum prospicit, iam ea figura et habitu gaudens, quo satis manifeste cognosci possit; figura nempe oblonga, conoidea, extremitate superiori angustiori, ex oesophago continuata, inde paulo antrorsum curvatus descendit, et apertura inferiori denique terminatur. Haec apertura ventriculi, quae prius foveae cardiacae hiatus fuit, tenero limbo cingitur, qui deorsum in plicas intestinales continuatur.

In the anterior side of the thorax the stomach, that in second day was anteriorly directed, now is obliquely turned below, already cheering to possess that aspect and that conformation by which it can be recognized rather clearly; in fact the aspect is lengthened, shaped like a cone, with the superior extremity more narrow in continuation with the oesophagus, then, bending itself a little bit forward, it goes down and finally ends with the inferior opening. This opening of the stomach, that previously had been the opening of the cardiac fossa, is surrounded by a soft edge continuing below in the intestinal plicae.

Retro ventriculum mesenterium, e duabus plicis mesentericis sibi appropinquatis et connatis formatum, continuatur ita ut laminae, ex quibus constat, prius planae, nunc erectae et unitae membranam simplicem referant.

Behind the stomach, the mesentery, formed by two mesenteric plicae each other approached and born together, continues in such a way that the laminae, by which it is constituted, previously flat, now erected and united, are similar to a simple membrane.

[57] Intestinum rectum infundibuliforme apparet, apice oblique deorsum retrorsum, hiatu sursum antrorsum collocatum. Ille in anum abit, hic aperturam et foveolam inferiorem, (caudae involucrum,) constituit.

The rectum appears shaped like a funnel, placed with the apex obliquely arranged below and backwards, with the opening upward and forward. The first one passes in the anus, the second one constitutes the opening and the inferior dimple (wrap of the tail).

Pelvis intestini recti, quod suscipit, formam aemulatur; nam pelvis priori tempore similiter sub plicae specie exterius circa plicam intestinalem et involucrum caudae {positus} <posita> apparuit plicasque abdominales conjungens, nunc marginem pubis refert.

The pelvis imitates the shape of the housed rectum; in fact the pelvis in a first time appeared in a similar way arranged with the shape of a plica more outside around the intestinal plica and the wrap of the tail, and connecting the abdominal plicae, now it seems the edge of the pubes.

Ex hoc margine blastoderma circa superficiem dorsalem foetus reflectitur, et ibidem limbo semilunari terminatur. Fines hujus limbi in illam membranam, ex plicis abdominalibus vel super dorsalem embryonis regionem reflexam et inde in dorsalem vaginae capitis partem transeunt. Haec reflexa membrana, quod est amnii veri inchoamentum, in axi dorsi nondum connata est et hac ratione recessus oblongo {laceolatus} <lanceolatus> proxime supra dorsum efficitur, a cujus margine membrana serosa in blastoderma continuatur[9]; [58] amnium, vocamus spurium, formans, quanquam nos non fugit, rem toto coelo diversam eodem nomine a Cl. Wolffio esse insignitam.

From this edge the blastoderma reflects around the dorsal surface of the fetus, and always here it ends in a semi lunar edge. The edges of this border pass in that reflecting membrane from the abdominal plicae or above the dorsal region of the embryo, and hence in the dorsal part of the wrap of the head. This reflected membrane, since it is the sketch of the true amnion, is not yet born in the axis of the back and for this reason a recess is created with the shape of a lance placed near lengthwise above the back, from whose edge the serous membrane continues in the blastoderma; forming an amnion that I call spurious, even if it doesn't escape me that a completely different thing is marked with the same name by the very illustrious Kaspar Wolff.

Interea plicae abdominales et intestinales, quae propter connexionem membranae serosae et vasculosae blastodermatis ex ea, ipso integro blastodermate, formari videbantur, a se invicem diversis in locis, praecipue, ubi futura pedum alarumque sedes est, solvi incipiunt; ita, ut progerminatio extremitatum accumulatione materiae cellulosae jam dignoscatur, et vestigium indicetur separationis futurae stratorum serosi et vasculosi, quam die quarto manifeste videbimus, quo tempore et amnion a sola membrana serosa et intestina a vasculosa cum adnexa pituitosa formantur.

In the meantime the abdominal and intestinal plicae, that because of the connection to the serous and vascular membrane of the blastoderma, being intact the blastoderma itself, seemed to be formed from it, start to reciprocally detach themselves each other in different points, above all where the future place of legs and wings is located; so that, in order that by now the precocious germination of the extremities is recognized because of the accumulation of cellular material, and a trace of the future separation of the serous and vascular layers is pointed out, that we will clearly see at the fourth day, a moment when both the amnion from the only serous membrane and the bowels from the vascular one are formed, with attached the pituitosa one <- mucous>.

In inferiore embryonis parte apparet vesicula lentis magnitudine, tenera vasculosa, pellucido liquore impleta, quae quasi de vasculoso pedunculo pendet; oritur ex apice intestini recti, ubi pelvis inchoamento obtegitur, arterias umbilicales, nempe ramificationes arteriarum iliacarum, quas supra vidimus, utrinque ad vertebras discendentes, suscipiens. Quam vesiculam [59] Chorion[10] vulgo appellant, Oken[11] autem cum Allantoide[12] mammalium comparat.

In the inferior part of the embryo a vesicle of the size of a lentil appears, tender, vascular, full of transparent liquid, that almost hangs from the vascular peduncle; it is born from the apex of the rectum, where it is covered by the sketch of the pelvis, housing the umbilical arteries, that is, the ramifications of the iliac arteries, that before we have seen to go down at both sides toward the vertebrae. Commonly they call chorion this vesicle, but Lorenz Ocken compares it to the allantois of the mammals.

Wolff hoc tempore renes sub figura laminarum angustarum longitudinalium et solutos a laminis mesenterii, quibus hactenus adhaerebant, vidit; et hepatis duos lobos et pulmonum vesiculas distinxit.

Kaspar Wolff in this moment has seen the kidneys under the aspect of longitudinal narrow laminae and detached from the laminae of the mesentery to which they were sticking till now; and he distinguished the two lobes of the liver and the vesicles of the lungs.

Oculi decolores apparent, palpebrisque nudi, neque praeter lentem crystallinam, atque vitreum corpus et circumpositas pellucidas membranas scleroticam et choroideam[13], quidquam apparet[14].

The eyes appear discoloured and without eyelids, and nothing is appearing except the crystalline lens and the vitreous body, as well as the transparent membranes placed around, the sclerotic and the choroid.