452 
GEOFF KEY SMITH AND EDGAR SCHUSTER. 
This has been fully confirmed by Shattock and Seligmann ( 8 ), 
who affirm the continued life of the germinal tissue. 
According to Foges (7) the allo-transplantation of testes or 
pieces of testis from one animal into another invariably fails,, 
the graft being absorbed. 
BibberFs observations led him to conclude that in the 
case of the thyroid auto-transplantation was successful, but 
allo-transplantation always ended in absorption. In his 
experiments with the auto-transplanted ovaries of guinea- 
pigs the ripe follicles discharged and atrophied, and after 
about fifty days new follicles grew and came to maturity 
with normal corpora lutea formation. 
On the other hand, his auto-transplantations of guinea-pig v 
testes were failures, complete degeneration setting in after 
twelve days, the epididymis nlone remaining normal. 
Marshall and Joly (9) carried out a series of auto- and 
allo-transplantations of the ovaries of rats, and their results 
show that the auto-transplanted grafts survived far better 
than the allo-transplantations; indeed, the disappearance of 
the germinal tissue in the latter cases seems to have been 
invariable. The allo-transplantations seem to have been 
more successful when performed upon closely related females. 
On the whole, the above evidence strongly supports the 
fundamentally different results obtained in the case of auto- 
and allo-transplantation, in the former case the young 
germinal tissue surviving, in the latter being destroyed and 
absorbed. 
We find it difficult to harmonise these and our own results 
with the experiments of Guthrie (12), in which he performed 
ovariotomy on hens, and grafted the ovaries of another breed 
into the operated hens. He claims that the allo-transplanted 
ovaries became functional and produced fertile eggs and 
chicks, which partook of the characters of the hen to which 
the ovary originally belonged. There are, however, two 
possibilities here. The complete removal of the ovary from 
a hen is a notoriously difficult operation, as the germinal 
tissue is closely adherent to the walls of the inferior vena 
