No. 1.] ORIGIN OF HUMAN MONSTERS. 151 
Sections of the chorion indicate also that it is practically 
normal with the exception of some fibrinous masses between 
the villi. Otherwise there is no indication of a change in the 
structures of the villi nor in the syncytium. 
It is certainly possible that all of these slight changes took 
place during the twenty-four hours before the abortion, while 
the uterus was making ready to expel the ovum. 
No. 13. 
Ovum, 8 x 7 mm.; vesicle within, I.4 x .85 mm. 
From Professor His, Leipzig. 
This embryo is the well-known specimen No. 44 of the His 
collection. (See Anatomie mensch. Embryonen, IH, pp. 32 
and 87.) The ovum is not completely covered with villi. 
Fic. 13a.—Section through the umbilical vesicle and chorion of specimen 
No. 13, His’s No. 44. Blood corpuscles are seen within the cavity 
of the vesicle. > 30 times. 
Within there is a small double vesicle which appears to be 
the amnion lying upon the umbilical vesicle. Attached to the 
denser (umbilical) vesicle there are numerous fibrils which 
extend throughout the entire ccelom. 
This specimen promised to be, at the time Professor His 
described it, the valuable early stage sought for by all em- 
bryologists, but unfortunately the sections prove it to be path- 
ological. The great quantity of fibrils, magma _ reticulé, 
within the coelom already indicated that the embryo is not 
normal. 
