No. 1.] ORIGIN OF HUMAN MONSTERS. 13 
variety of monster can never be predicted, and if there are 
a number of them they are usually of mixed types.” 
What I have to say in this publication of monsters applies 
only merosomatous terata which are not of an hereditary 
nature and are no doubt produced by agents which interfere 
with the nutrition of the embryo. Having taken only those 
monsters from which the germinal factor is excluded, it 
makes it necessary once more to consider some minor me- 
chanical agents as their cause, which may be termed a modified 
mechanical theory. 
The advocates of the mechanical theory gradually lost 
ground, for they had to combat the germinal theory on the one 
hand, and on the other they were compelled to state that me- 
chanical influences, generally those due to lacing, caused the 
foetus to become monstrous by the pressure that was exerted 
upon it. The theory was then modified to include primarily 
intra-abdominal influences like tumors, malformations of the 
pelvis and uterus, as well as those within the ovum itself. 
Gradually we see less and less weight placed upon any of these 
specific causes, and finally the modern advocates of the theory 
believe that amniotic bands and adhesions are the main influ- 
ences in the production of monstrosities. It is needless to 
state that each advocate had his own combination of circum- 
stances, and when all of them are taken together, with modi- 
fications and exceptions, it is practically impossible to make 
general statements. Suffice to say that the objections to each 
form of the theory appear to be sufficient to explode the 
whole theory, and to the bulk of physicians maternal influ- 
ences seem to be as rational a cause in the production of 
monsters as mechanical influences, for the data of experience 
are about as good in the former as in the latter. 
There are some rare cases of spontaneous amputation of 
the extremities which are said to be due to pressure of the 
umbilical cord. However, these cases can be separated into 
two marked groups, one in which there is an actual amputa- 
*Bardeen, Jour. of Experimental Zool., 1907. 
