No. 1.] ORIGIN OF HUMAN MONSTERS. 123 
the body are necrotic, and most of them are infiltrated with 
round cells, and there is irregular growth of the mesodermal 
tissues, especially those of the tendons and perichondrium. 
The embryos of the second portion of the sixth week, that 
is, embryos 15, 16 and 17 mm. long, may be brought together 
in three groups, according to the degree of change in their 
tissues. 
In the first group there are three specimens, Nos. 263d, 
132 and 188. In these the first changes are seen after the 
circulation has been cut off. The tissues and organs are 
sharply defined, the vascular system is distended with blood, 
and more or less round cells are found inthem. ‘The fore-brain 
is solid and the medulla and cord are somewhat dissociated. 
In No. 263d the brain has broken through the palate and a 
considerable amount of it has escaped into the mouth. How- 
ever, this embryo is macerated somewhat and is slightly torn 
in the region of the back, and the brain capsule may have 
been torn open by mechanical means. In embryo No. 132 
the extremities of the right side of the body are atrophic, 
while those of the left appear to be normal. 
In the second group of specimens (Nos. 344, 137 and 357) 
the changes in the embryo are more marked. The blood- 
vessels are gorged, their walls are not sharply defined and the 
blood cells extend from them into the surrounding tissues. In 
No. 344 the brain is reduced in size, is solid and occupies but 
a small portion of the head. The medulla is dissociated and 
expanded and has been pushed forward, almost reaching to 
the front part of the head. Below this the jaw is kinked over 
the chest, with which it has formed a secondary union. Over 
the regions of the fore-brain and mid-brain there are spots 
in which all of the surrounding tissue is wanting entirely, 
thus exposing the brain freely at these points. 
The last group includes the embryos in which the changes 
are extreme, and includes seven specimens, Nos. 81, 142, 200, 
212, 215, 339 and 364. In them the tissues are well disso- 
ciated and more or less filled with round cells. The usual 
changes are seen in the central nervous system, the spinal 
