454 
GEOFFREY SMITH AND EDGAR SCHUSTER. 
This process is exceedingly rapid in the case of the cock, less 
rapid in the rabbit, and comparatively slow in the frog. 
Now, if we suppose that the presence of the testis in an 
abnormal situation leads to inflammation and a rich vasculari- 
sation uncontrolled by the normal nervous supply, we can 
understand how the spermatozoa, even in an auto-transplanted 
testis, come to be damaged and destroyed, and the process, 
once begun, would continue with increasing magnitude as the 
presence of damaged spermatozoa with their debris led to 
further inflammation. The survival of the spermatogunia in 
the auto-transplanted testes and their destruction in the allo- 
transplantations indicate that the blood and body fluids of 
an individual are less toxic to its own embryonic cells than 
the blood of another individual, and also less toxic to its own 
spermatogonia than to its own fully formed spermatozoa. 
The Effects of Ovariotomy, Castration, Transplantation, 
ETC., ON THE PROPERTIES OF THE THUMB-PAD. 
We will, first of all, give the experiments on females which 
were designed to test whether the removal of the ovaries, 
with or without transplantation of testes or injection of testis 
extract, caused the thumb to swell or become rough and 
pigmented. Certain of the frogs used have already been 
referred to in preceding experiments, and they are referred 
to by the same numbers. 
INo. 3. — Female frog, ovaries removed and two testes 
implanted September 30th, 1909. February 10th, 1910. 
Testes pieces inserted in dorsal lymph-sac. 
March 3rd, 1910. Injected 1 c.c. testis extract. 
March 6th, 1910. Ditto. 
March 10th, 1910. Ditto. 
March 14th, 1910. Ditto. 
March 18th, 1910. Ditto. 
The injections were made with sterile saline into the dorsal 
lymph sac; altogether the substance of twenty-three testes 
was injected. 
