No. 1.] ORIGIN OF HUMAN MONSTERS. 187 
The entire ovum was covered with villi, apparently normal, 
but surrounded by a layer of pus and blood. After opening 
it I found the ccelom filled with a mass of coagulated fibrin- 
ous albumin, the magma reticulé, within which no embryo 
could be seen. ‘The two halves of the ovum were then stained, 
which brought out prominently a small vesicle imbedded in 
the magma. This vesicle had a rounded opening upon one 
side (Fig. a), with a long pedicle upon the other, which ex- 
tended towards but was not attached to a small mound on the 
inside of the chorion. Vesicle and chorion were both cut into 
serial sections. 
The sections of the vesicle appear as those of the normal 
umbilical vesicle. The opening on the side is undoubtedly 
due to a tear, judging by its broken edges. 
B (e 
<p» 
Fic. 123d.—Section through the vesicle. > 25 times. Entoderm, meso- 
derm and blood islands are shown. 
