164 APPENDAGES OF THE FCETUS. 



the amniotic membrane and the epidermis, but that this continuity is 

 afterwards difficult to deny. 



425. It also follows, that the amnios is far from touching the in- 

 ternal surface of the chorion at all periods of pregnancy, as is gene- 

 rally supposed, but that these two membranes are, on the contrary, 

 separated from each other by a considerable space, during a period 

 which differs in different individuals. 



This space, which is at first very large in proportion to the cavity 

 of tlie chorion, much larger than the amnios itself during the whole 

 of the first month, afterwards diminishes by degrees, in proportion 

 to the increase of the amnios, so that at two months it about equals 

 that which separates the embryo from its envelop; at length the 

 disproportional growth of this last named membrane causes it to dis- 

 appear almost entirely, so that towards the fourth or fifth month we 

 are obliged to suspect, in order to be able to recognise its exis- 

 tence. 



426. It is useless to repeat what I have said as to the non-exist- 

 ence of vessels in the proper tissue of the chorion, for the purpose 

 of showing that they are far more certainly wanting in the amnios: 

 indeed, nothing leads us to admit of their existence in the latter; it 

 is never covered with villi like the former; it never has any intimate 

 connection with any vascular organ, and all that has been said upon 

 the subject by various authors, in fact, consists of mere assertions, or 

 rather of pure suppositions. 



As the remarks in this article prove evidently that the amnios 

 forms only one single coat at the various periods of gestation, I shall 

 not stop to combat those who have thought it to be composed of 

 several layers in the commencement of its development. 



§. III. Of the l¥ater of the Amnios. 



427. Besides the fostus and the cord, the amnios contains a fluid 

 called the water of the amnios, or amniotic liquor. 



428. At the beginning these waters form but a thin stratum; their 

 proportional quantity afterwards increases rapidly, until towards the 

 end of the second month, when the inner membrane of the ovum 

 comes in contact with the chorion: at three months the weight of 

 the amniotic fluid considerably exceeds that of the foetus; but at 

 term the weight of the foetus, in turn, considerably exceeds that of 

 the fluid in which it floats. At birth, in fact, there are commonly 

 not more than from ten to thirty ounces of fluid. However, it would 

 not be correct to say, with Madame Boivin and several others, that 

 the quantity of fluid diminishes in an absolute manner from the mid- 

 dle of pregnancy until the moment of parturition. It is, on tiie con- 



