No: 1] ORIGIN OF HUMAN MONSTERS. 71 
amnion and embryo, leaving only the umbilical vesicle, which 
may be found either attached to the chorion or lying free in 
the ccelom. 
During this period, while the ccelom is relatively very large, 
a disturbance in the transmission of nutritive substances from 
the decidua to the embryo is marked by an increase in the 
reticular magma of the celom. This delicate reticulum was 
first described about a century ago and is pretty well marked 
in normal ova. As the amnion expands to fill the ccelom the 
magma reticulé is gradually pushed before it and often 
remains for a time as a delicate layer between the amnion 
and chorion. When the embryo and amnion are more or 
less destroyed the magma reticulé gradually becomes denser 
and denser, encircles the umbilical vesicle and fills the ccelom. 
In case the amnion is still intact but does not fill the cavity 
of the chorion entirely, pathological ova are usually marked 
by a mass of dense magma in the exoccelom. This change in 
the structure of the magma is so well pronounced in early 
pathological ova that specimens which are believed to be 
normal on account of a perfect villous covering are at once 
recognized as being diseased as soon as they are opened. 
The nature of the magma is not known. I have made 
numerous tests with Weigert’s fibrin stain, but in no case did 
the fibers take on the color. Neither do they appear to be 
related to ordinary reticulated tissue, which is present in the 
embryonic state in the mesoderm of the chorion, for they are 
not connected in any way with the protoplasm of these cells. 
As the magma reticulé becomes more pronounced in path- 
- ological specimens it is often converted into, or is intermixed 
with, a granular substance which may be termed the granular 
magma. In case the ovum grows to be large, as is speci- 
men No. 115, the reticular magma is often destroyed, leav- 
ing only the granular substance, more or less mixed with 
fluid to fill the ccelom. In older specimens we often see the 
cavity of the amnion filled with a mass of granular magma, 
while the surrounding ccelom is filled with reticular magma. 
However, stained sections show this separation only in a 
