456 
GEOFFREY SMITH AND EDGAR SCHUSTER. 
If castration is performed in the summer months, May to 
July, when the thumb-pads are normally small, compara- 
tively smooth and uupigrnented, the thumb-pads remain in 
this condition and do not develop the swolleu glands or 
prominent papillae the following autumn or winter. Thus — 
No. 14. — Male frog, had both testes removed July 16th, 
1909. At this time the thumb was smooth and unpigmented 
(fig. 23). It remained in this condition without any alteration 
until April 23rd, 1910, when it died. 
If castration is performed during the autumn or winter 
months, when the thumb has begun to acquire its marked 
papillae, glands, and pigmentation, the act of castration 
does not cause any disappearance of the papillae or 
Text-fig. D 
Camera drawing of outline of part of thumb-pad of male frog. No. 15, 
5| months after complete castration. 
glands, but they remain in the condition in which 
they were when castration was effected for an 
apparently indefinite period. Thus — 
No. 15. — Male frog, with moderately rougli and swollen 
pads, was castrated on September 29th, 1910. Observations 
were made on this frog for a considerable time, but it was 
impossible to tell from inspection whether the pads decreased 
in size, or the papillae were reduced. The animal was killed 
on March 9tli, 1911, i.e. after a period of 5^ months, 
and drawings of part of the thumb-pad in a whole preparation 
(Text- fig. D) and of sections (fig. 24) are given. Marked 
papillae are present, and a certain amount of pigment. The 
glands are swollen aud well developed ; in fact, the whole 
pad is in a condition normal for a September frog. There is 
