ATAVISM OR REVERSION. 153 
veloped to the same extent as in the functional male. 
It must also be borne in mind, that in cases where sterile 
females, or those which have ceased to bear young, put 
on external male characters, they rarely attain such pro- 
portions or beauty as in the male ; for in the males the 
general excitement produced by sexual passion has a 
most powerful stimulant effect upon the growth and 
development of these structures, which is wanting in 
the female. So that in her occasional attempts to 
emulate the male she succeeds to a certain degree, but 
rarely, if ever, attains to so good a condition. 
Hunter has recorded some experiments which have a 
bearing on this matter :— 
“T wished also to ascertain if the parts peculiar to the 
male could grow on the female, and if the parts of a 
female, on the contrary, would grow on a male. 
Although I had formerly transplanted the testicles 
. of a cock into the abdomen of a hen, and they had some- 
times taken root there, but not frequently, and then had 
never come to perfection, yet the experiment could not, 
from this cause, answer fully the intended purpose ; there 
is, I believe, a natural reason to believe it could not, and 
the experiment was therefore disregarded. I took the 
spur from the leg of a young cock, and placed it in the 
situation of the spur in the leg of a hen-chicken ; it took 
root, the chicken grew to a hen, but at first no spur grew, 
while the spur that was left on the other leg of the cock 
grew as usual. This experiment I have repeated several 
times in the same manner, with the same effects, which 
led me to conceive that the spur of a cock would not 
grow upon a hen, and that they were, therefore, to be 
