48 MALL. [Vor, XIX. 
until the foetus is well formed. The leg bud is filled with con- 
densed mesenchyme and is irregular in shape, sometimes being 
stubby on one side of the body and normal on the other. The 
study of the larger embryos shows that there is a kind of 
“inflammation” in the deformed extremity, there being an 
“infiltration”? of cells, which is especially well marked in the 
tendons and around the cartilages. In general, this condition 
may be accounted for by a general arrest of development due 
to impaired nutrition. At any rate, embryos that are not 
developing well, experimental larve, and human embryos with 
other malformations, often have club-shaped arms, legs, fins 
and tails. 
PATHOEOGICAL OVA: 
As we pass up the vertebrate scale it becomes more and 
more difficult to ascertain the primary causes which produce 
pathological ova, and prestmably monsters. In fact, the 
causal study of teratogenesis has been and still is one of the 
capital problems in medicine which is gradually being solved 
by anatomists. It has been stated repeatedly in this paper 
that the missing link to complete the chain of evidence is to 
be found in the careful study of aborted ova which are found 
to be more or less diseased. In the excellent monograph by 
Granville’ we find a report of the study of forty-five aborted 
ova, from which he concludes that the chorion is first diseased, 
which naturally results in retarding the growth of the embryo. 
He notes that an inflammatory condition must have been 
present in the uterus, for the abortion of pathological ova is 
usually accompanied with great pain and an excess of hemor- 
rhage. 
I have been unable to obtain valuable data regarding the 
condition of the uterus in early abortions from pathological, 
gynecological or obstetrical literature. It is all clouded in 
"Granville, Graphic Illustrations of Abortion, London, 1834. 
