1910-11.] Bone Growth in absence of Functioning Testicles. 121 
This group of observations yields evidence in support of the hypothesis 
that the disturbances in the normal structural proportions found in the 
body of subject A 9 were the direct result of his testicular failure. Their 
evidence is strengthened by a study of the effects of the castration of 
healthy young animals. 
The observations dealing with this matter constitute Group B. 
GROUP B. 
Observations upon the Effects of Castration in Animals. 
Observation B 1 (1). 
A. Two cocks of the same brood and of the same strain (Ardennes) 
were selected. 
B. Two cocks of the same brood and of the same strain (Italian) were 
selected. 
One animal in each pair was castrated, the other kept entire. They 
are distinguished as A. Capon, A. Cock, and B. Capon, B. Cock. 
Before the operation was performed the weights of the animals were — 
A. Cock . 
980 grammes. 
A. Capon 
. 845 
B. Cock . 
. 785 
B. Capon 
. 805 
The age of all the animals was 
3 months and 12 days. 
Eight months after operation 
ights were — 
the animals were killed, when 
A. Cock . 
1955 grammes. 
A. Capon 
. 2800 
B. Cock . 
. 2105 
B. Capon 
. 2650 
On examination, the bodies of the capons were found to be much fatter 
than those of the cocks. 
Examination of the Skeleton. 
The bones of the capons were longer, thicker, and denser than those of 
the cocks. The actual measurements of the long bones and the percentage 
increase of the bones of the capons are shown in Table XXXI. 
