No. 1.] ORIGIN OF HUMAN MONSTERS. IOI 
is lined entirely by the amnion, the cavity of which is 35 mm. 
in diameter. It is interesting to note that this ovum has 
reached its maximum growth without the presence of a vigor- 
ous embryo. Ova without embryos rarely exceed 40 mm. in 
diameter, and in normal development the amnion reaches the 
chorion and obliterates the exoccelom in ova of this size. If 
the cavity of the amnion is to exceed 40 mm. in diameter, it 
is necessary to have a fairly active embryo within it to secrete 
the liquor amnii. As long as there is an exoccelom present, 
which is not obstructed by magma reticulé, it appears as if 
fluid of the amnion is obtained from that of the ccelom. 
In this specimen (No. 321) the embryo is attached to the 
chorion at its middle, that is, there is no umbilical cord left. 
The body cavity of the embryo spreads out on the inside of 
the chorion, and into this the degenerated heart hangs. The 
dissociation of the tissues is pretty complete, as in No. 162. 
The outline of the brain is barely recognizable and all the 
tissue in the tail of the embryo is of equal density. Here the 
dissociation is complete. Unfortunately, the specimen had 
been preserved in 50 per cent alcohol for ten days before it 
was sent to me, and in a measure the extreme degree of dis- 
sociation may be due, in part at least, to the macerative influ- 
ence of the weak alcohol. However, this could not alter the 
general outline of the embryo and its organs. 
No. 12 is extremely interesting, for it also is probably 
pathological, although I have often referred to it as being 
normal. When it came to me I found considerable magma 
in the coelom, enough to almost obscure the embryo, but on 
account of the general normal structure of the tissues I over- 
looked the excess of magma. More careful investigation of 
the chorion shows that there are also some fibrinous or mucoid 
masses between the villi. They also indicate that the speci- 
men is not quite normal. Furthermore, there is a marked 
anencephaly and probably the beginning of spina bifida pres- 
ent. Before a definite opinion can be given regarding the 
normality of this specimen it will be necessary to examine 
with much greater care than has been done the tissues of the 
