AMNIOS. 163 



of the chorion, '^ust have been from two months and a half to three 

 mouths old, but which, from the size of the embryo, seemed not to 

 be more ihan four or Jive weeks, the amnios was a sac three or four 

 times smaller than the chorion, and was reflected along the cord 

 at the distance of a line and a half from its root, so as to give it a 

 sheath quile up to the belly. This amnios, besides, presented all 

 the characters of the normal state. 



In an ovum of six or seven zveeks, presented to me by Madame 

 Lachapelle, the amnios, nearly as large as the chorion, had begun 

 to reflect itself in the form of a funnel upon the cord, at the distance 

 of six lines from the navel, which it reached after enveloping the 

 vessels, the pedicle of the vitelline sac, the intestinal bulb, &;c. 



In another older ovum, which was brought to me by M. Morisse, 

 an accoucheur at Paris, the amnios was still separated by a consi- 

 derable space from the chorion, and was applied to the cord so as 

 to sheathe it, beginning at the place where the prolongation of the 

 umbilical cord was implanted, and extending as far as the belly, 

 where, according to all appearances, it was continuous with the 

 epidermis. 



In a specimen of eight or nine weeks, which M. Boulon d' Abbe- 

 ville gave me, the external surface of the amnios touched, so to speak, 

 the chorion, and invested the whole of the cord, which, already very 

 long and spiral, still contained the intestinal mass in one of its en- 

 largements. 



In one of at least three months, very perfect, which M. Morisse 

 procured for me twenty-four hours after it had been passed by the 

 woman, the epidermis was so entirely separated from the other pans 

 of the fcetus by a thick stratum of slightly muddy serum, that it might 

 have been removed with the greatest ease; the same was observed 

 along the cord from one end to the other; only the pellicle was here 

 close to the vessels at four different points which gave rise to four 

 contractions and four vesicles placed at equal distances; but the 

 adhesions of the amnios at the contracted spaces of the umbilical 

 cord, and those that the epidermis had preserved with some portions 

 of the limbs, did not prevent me from remarking the most perfect 

 continuity between all these lamellae. 



424. From these notions it follows, that during the first fortnight 

 of gestation, the amnios has no immediate connection with the foetal 

 end of the umbilical cord, on which, at a somewhat later period, it 

 doubles, so as to furnish it with a sheath, and place itself in contact 

 with the inner surface of the chorion; that this disposition is main- 

 tained, saving in a few exceptions, until the abdominal parieies are 

 completely formed; that until then there is no continuity between 



