STUDIES IN THE EXPERIMENTAL ANALYSIS OE SEX. 445 
1910. Time in body of female, 1J months. Testis found 
attached in two places to bladder and ovary; a small vascular 
supply was present from capillaries of these organs. Sections 
show the presence of a considerable number of blood-vessels 
round the edge of the testis. The testis tubules show distinct 
signs of degeneration both in the ripe spermatozoa aud in the 
spermatogonia lining the tubules, although they are still 
present. It has not undergone any marked reduction in size. 
There is no increase of fibrous tissue. 
No. 2. — Female frog, with one testis from male frog A., 
implanted September 29th, 1910. Killed December 15th, 
1910. Time in body of female, less than three months. 
Testis enclosed in a fold of peritoneum near the bladder, 
vascularised from superior abdominal vein and mesenteric 
blood-vessels. A band of fibrous tissue (PI. 43, fig. 1, fi.) is 
conspicuous on the side of attachment of the testis to the 
host, which is probably invasive fibrous tissue derived from 
the host. There is marked degeneration of the spermatozoa 
in the tubules, many of them being broken up into irregular 
masses of chromatin, among which some phagocytes can be 
recognised which have engulfed the chromatin lumps derived 
from spermatozoa. The degeneration of the tubules has 
proceeded more rapidly towards the side of attachment than 
along the free edge. The majority of the spermatogonia have 
disappeared, but traces can still be seen chiefly round the 
periphery of the organ. 
No. 3. — Female frog, ovaries removed, and two testes 
implanted September 30th, 1909. Died March 24th, 1910. 
Time in body, six months. Both testes found intact, attached 
to peritoneum, with blood supply from ovarian mesentery and 
anterior abdominal. In both testes (vide PI. 43, fig. 2) the 
tubules are disintegrating, the spermatogonia have all dis- 
appeared, and the spermatozoa are broken down into masses 
and granules of chromatic material. Among the tubules are 
very numerous phagocytes (fig. 3), which appear to be devouring 
the chromatin clumps derived from the degenerate spermatozoa. 
Iu both testes there is a broad strip of fibrous tissue along 
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