STUDIES IN THE EXPERIMENTAL ANALYSIS OF SEX. 461 
have again begun to develop, we do not find that the papillae 
are reduced as the result of castration, but that six months 
after castration the papilias are in much the same condition 
as they were when castration was performed. Now, if we 
consider Nussbauin’s and Meisenheimer’s experiments in the 
light of these facts, also in the light of the entirely negative 
results obtained by us as the result of transplantation and 
injection of testis pieces or extract, we find that there is 
grave reason to doubt whether the positive results claimed 
by these authors are really conclusive. 
Taking Nussbaum’s experiments first, we may note that he 
is of opinion that castration may lead to a reduction in size of 
the papillae, though this result, which is at variance with our 
own, is apparently obtained from mere inspection of the 
thumb at the beginning* of the experiment, while at the close 
figures are given of microscopical preparations. 
In two cases definitely positive results are claimed as the 
result of injecting castrated frogs with testis extract or of 
implanting pieces of testis in the dorsal lymph-sac. 
In one case the frog was castrated on June 18th, when the 
pads are said to have been small and without papillae. No 
drawing is given of the state of the pad at this time, and we 
suppose that the statement that the pad was without papillae is 
based on inspection and not a careful examination under the 
microscope. In the other experiment the frog was castrated 
on May 26th, and a similar statement is made as to the state 
of the pad, but no drawings are given. During September 
and October both frogs were injected with testis extract or 
had pieces of testis implanted in them, and it is stated that the 
roughness on the thumb developed increasingly. As a proof 
that the growth of the papillae is the result of testis injection, 
Nussbaum gives several figures, but in none of them is the 
condition of the pad before the experiment depicted, com- 
parisons being instituted merely between the condition of the 
pad at the close of the experiment and that of a pad belonging 
to some other frog differently treated. Now without wish- 
ing to throw the least doubt on the good faith of these 
VOL. 57, PART 4. NEW SERIES. 34 
