No. 1.] ORIGIN OF HUMAN MONSTERS. 25 
the primary trouble cannot be due to the presence of poisons 
in the blood of the mother, to correspond with chemicals used 
by teratologists in producing lithium larvz, for instance, nor 
to a fever, to correspond with the changes in temperature 
used to produce chick monsters. The process in man is quite 
different, being due probably to faulty implantation of the 
ovum, which naturally affects the growth of the embryo. 
This will be discussed under a subsequent heading. 
EXPERIMENTS WITH SALTS OF POTASSIUM AND CHANGES OF 
THE EMBRYO ESPECIALLY MARKED IN THE HEART. 
In case interference in the nutrition of the embryo is not too 
great the growth of part of the embryo, instead of all of it, may 
be retarded, with an additional destruction of tissue, thus pro- 
ducing the partial monsters in man, which frequently develop to 
full term. However, there is every kind of gradation between 
total and partial monsters, the former often showing many 
indications of the latter and the latter are frequently multiple. 
A total monster may have spina bifida, hare-lip, anencephaly, 
club-foot, cyclopia, etc., and a partial monster may include 
several of these types.. The primary affection which is to 
produce a pure spina bifida in man must be slight, must come 
at the right time, and subsequently the faulty implantation 
must be remedied so that the embryo may continue to ‘grow. 
In order to make my standpoint clear I shall first give 
some data regarding the frequency of some types of monsters 
as well as some experiments which show that the heart is 
extremely susceptible, its growth being easily retarded and 
often arrested after the embryo is well formed. 
Von Winckel has given us some data regarding 87 mon- 
sters obtained from 12,378 births in Dresden, that is, there 
*Von Winckel, Ueber die mensch]. Missbildungen, Samml. klin. 
Vortrage, Leipzig, 1904. 
