[66] §. 13.
Dies quintus.

§ 12
Fifth day

Membrana vitelli propria evanuit.

The proper membrane of the yolk disappeared.

[67] Amnium spurium membranae testae, ubi illi proximum, adhaeret.

A spurious amnion sticks to the membrane of the shell in the point where is near to it.

Amnium verum clausum.

The true amnion is closed.

Chorion auctum, cum amnio spurio, cui subjacet, concrescit.

The increased chorion grows together with the spurious amnion under which it is located.

Magna sinus terminalis venarumque descendentis et adscendentis in area vasculosa accidit mutatio; ille fere evanuit et hae quoque jam incipiunt se oculis [68] subducere et disparere, ita ut post aliquot dies ne ullum quidem earum vestigium supersit.

In the vascular area a great mutation happens of the terminal sinus as well as of  descending and ascending veins; it nearly disappeared and also the veins by now start to go away and to separate from the eyes, so that after some days really no trace of them remains.

Intestinum medium totum fere clausum est; plicae intestinales sibi approximatae et coalitae nullam nisi per parvum canalem vitello-intestinalem, intestini cum vitello communicationem permittunt.

The middle bowel is nearly all closed; the intestinal plicae, approached and fused each other, don't allow any communication of the bowel with the yolk but through a little yolk-intestinal channel.

Membrana serosa et vasculosa a se invicem omnino separatis, haec prior a limbo umbilici, angustiore facto, super dorsum in amnii membranam abit; posterior una cum pituitosa vitellum proxime includit et intermedii canalis vitello-intestinalis ope cum intestino conjungitur.

Being the serous and vascular membrane wholly separated from each other, the first of them goes away from the edge of the navel, which became more narrow, above the back toward the membrane of the amnion; the other membrane, together with the mucous one, houses narrowly the yolk, and by the yolk-intestinal intermediary channel joins to bowel.

Ne plane cerebri rationes praetermisisse videamur, adnotamus haec pauca. Medulla spinalis sub angulo obtuso inflexa continuatur in medullam oblongatam; ubi partes laterales medullae sejunctae a se invicem patentem ventriculum quartum exhibent. Simulatque propius ad corpora quadrigemina accesserunt pontis in speciem utrinque concretae partem anteriorem ventriculi quarti obtegunt.

So that it doesn't seem that I have wholly put aside the reasonings of the brain, I make a note of these few things. The spinal marrow, folded under the obtuse angle, continues in the medulla oblongata; where the lateral parts of the marrow, separated each other, show an evident fourth ventricle. As soon as with the shape of a bridge they more approached the quadrigeminal bodies, united at both sides they cover the anterior part of the fourth ventricle.

Corpora quadrigemina sub forma vesiculae per longitudinem a parte posteriori ad anteriorem usque paullulum [69] insectae conspiciuntur. Ab utroque latere horum corporum laminae duae proficiscuntur parallelae ad hemisphaeria, quae pari modo vesicula insecta includuntur et comprehenduntur.

The quadrigeminal bodies are seen in the shape of slightly jagged vesicle in its length from the rear until the anterior part. From both sides of these bodies two parallel laminae depart in direction of the hemispheres, which in the same manner are shut up and housed by a jagged vesicle.

Verumtamen nondum satis liquet, neque sine magno negotio ad liquidum perduci posse videtur, utrum quae vidimus veram cerebri substantiam constituant an sint membranae, quae cerebrum perfectum includant, praesertim magna nobis circa haec dubia moverunt Viri clarissimi Wenzel[1] eo, quod in praestantissimo opere "de penitiori structura cerebri humani et brutorum"[2] tradunt, incubationis die sexto massam cerebri adeo mollem esse, ut veluti mucus difflueret, quo factum esset, ut nulla singularium cerebri partium, si quae jam modo adfuissent, dignosci posset.

However to say the truth it is not yet enough clear, neither it seems that it can be traced back to liquid without a great effort, if those things I have seen are constituting the true substance of the brain or are membranes holding the completed brain; above all they made me to reflect, upon these for me big doubts, the illustrious men Joseph and Karl Wenzel, because in the excellent work De penitiori structura cerebri hominis et brutorum – About the more inner structure of the brain of man and of beings devoid of reason – they report that at the sixth day of incubation the mass of the brain is soft to such a point to flow out as being mucus, so it happened that none of the single parts of the brain could be recognized, provided that already they were present.