34 ABNORMAL CONDITIONS OF THE AXIS. 



It is probable that such included foetuses owe their origin to 

 very nearly the same conditions as those which give rise to other 

 forms of doubling. It is not easy to understand how a second 

 ovum could enter the body-cavity of an embryo, whilst there is 

 no difficulty in understanding how a second embryo on a common 

 yelk could be so included. The cyst under such circumstances 

 would owe its origin to a portion of the common amniotic sac, 

 which the included embryo must necessarily carry before it. It 

 is true no connexion has been observed between the cyst and the 

 umbilicus ; but all things considered, the above is the least impro- 

 bable means of accounting for the phenomenon. The disappear- 

 ance of a portion of the amnion in several years is by no means 

 inexplicable, especially when it is remembered that the membrane 

 must have been extremely thin at the time of its induplication. 



134. A portion of a cyst (which contained the foetus No. 135) 



from the abdomen of a well-formed male child aged be- 

 tween 9 and 10 months. The preparation includes a por- 

 tion of large and small intestine of the child. 

 The case is described by Mr. Gr. W. Young in the ' Med.-Chir. 

 Trans.' vol. i. p. 234. The cyst is recorded to have contained 78 

 ounces of fluid, and to have discharged a portion of its contents 

 several times into the peritoneal cavity ; it is further stated to 

 have been placed between the layers of the transverse mesocolon. 

 The same thing was also believed in M. Duptiytren's case*; but 

 much difficulty arises in the explanation of the phenomenon if such 

 really be the fact. In the present instance it will be seen that 

 the mesentery is likewise adherent to the cyst, and the whole mass 

 is so matted together that it would be impossible to determine 

 whether the cyst is between the layers of the mesocolon or not ; it 

 is much more probable that the cyst was originally placed between 

 the mesocolon and mesentery. The portion of the cyst which has 

 been preserved consists of a number of layers, a fact quite in 

 consonance with the opinion that it was originally formed by an 

 induplication of the amniotic sac. It is very thick, and presents 

 a villous surface within. The upper part of the cyst, which was 

 covered by the omentum, has not been preserved. It is stated to 

 have been very thin and transparent. 



Presented by G. W. Young, Esq. 



135. The imperfect foetus from the same, divided vertically to 

 * Bulletin de la Soc. de la Facultc de Med. Paris, an 13,no. 1, p. 4. 



Himly, Foetus in Fretn, p. 18. 



