No. 1.] ORIGIN OF HUMAN MONSTERS. 85 
valuable because they show the early changes in the chorion 
when its implantation is faulty. The structure of the main 
wall of the chorion and its villi is also more or less changed, 
as the table and histories of the specimens show. It is natural 
to read into these specimens the following history: The em- 
bryonic mass grew for some time, but was soon arrested 
because the chorion could not supply the proper nutrition. 
Soon the embryonic mass began to degenerate, and this 
process was only hastened by the secondary changes which 
were beginning in the villi, Soon the whole ovum was dis- 
organized, as we see by the study of the specimens. 
This group of specimens throws much light upon the pri- 
mary cause in the destruction of very young embryos. In 
five it is mechanical and in two it is clearly due to endome- 
tritis, although no secondary changes are found in the chorion. 
I have every reason to think that this kind of abortion is 
much more common than is believed to be, for physicians 
often have told me that they “found but lost, or threw away, 
suspicious specimens,” or that they “sought but failed to find 
small fcetuses in suspected abortions.’’ No doubt curing the 
endometritis in such cases would favor future pregnancies, as 
is generally believed by gynecologists. At any rate, for our 
purpose, these specimens show that impaired nutrition due 
to faulty implantation causes destruction of the embryo with- 
out making any marked impression upon the chorion. 
The first group of this series is no doubt composed of speci- 
mens of the second and third week of pregnancy, in which the 
whole embryo was destroyed and the ovum aborted before any 
change took place in the chorion. The next group includes 
ova of the third and fourth week, judging by their size, and 
by the presence of blood-vessels in the chorion of some of 
them. 
The smaller specimens of the second group also show no 
macroscopic changes in the chorion, but microscopic exami- 
nation tells a different story.. In specimen No. 299 there is 
a dense magma reticulé, and the mesoderm of the chorion and 
the villi appear to be cedematous. Nos. 395 and 181 tell the 
