No. 1.] ORIGIN OF HUMAN MONSTERS. 125 
changes are found in the chorion, indicating faulty implanta- 
tion and inflammation. The embryo, whose menstrual age 1s 
99 days, corresponds in length with a normal embryo 40 days 
old, that is, having a menstrual age of 68 days. In other 
words, the pathological process in No. 364 has been under 
way for fully a month. 
The large blood-vessels and heart are still filled with blood 
and there is a general infiltration of the tissues with round 
cells; the vessels of the umbilical cord do not reach to the 
chorion, showing that the nutrition of the embryo has been 
cut off entirely. There is a general destruction of the tissue 
due to, or causing, the irregular growth of the embryo. This 
is especially well marked in the brain and spinal cord, which 
are rudimentary, are converted into a mass of vascular con- 
nective tissue capped by a rudimentary shield of brain tissue, 
as is illustrated in the figures. . 
There is pronounced hare-lip, the ears are displaced, and 
there is exomphalos, spina bifida and pseudencephalus; the 
latter is no doubt the forerunner of anencephalus. 
That the pathological conditions found in most of the 
‘specimens reported in this contribution are not of germinal 
origin, but rather due to the changes in the environment of 
the ovum, as may be brought about by endometritis, is illus- 
trated beautifully by two sets of twins of the sixth week, 
which I have been fortunate enough to procure—one from 
Professor Brodel and the other from Professor Minot. To 
these may be added the twins of the fifth week (Nos. 330a 
and 330b), the two sets of specimens, each from the same 
woman (Nos. 110 and 141 and 308 and 325), kindly sent 
me by Drs. West and Ballard. These groups of specimens 
speak volumes against the germinal theory of merosomatous 
monsters. The facts of the case have been discussed under 
a special heading above, and they need not be repeated here. 
However, if the law of probability and the normal condition 
of the embryos in earlier pregnancies were not taken into 
consideration, they could be explained by the germinal, just 
as well as by the environmental theory. The conclusive evi- 
