364 
HERBERT H. BROWN. 
upon spermatogenesis, takes a different view. He considers 
that the connection between the spermatozoa and the support- 
ing cells is primary, both being derived from the division of a 
single cell. These cells are situated in the outer layer between 
the germinative cells of Sertoli, which, according to this ob- 
server, are follicular, and take no share in the production of 
spermatozoa. They divide in a radial direction into two cells, 
which do not entirely separate from one another. The external 
of the two remains in the resting condition attached to the wall 
of the tubule, and is called the spermatogonium, while the 
other cell increases in size and its nucleus repeatedly divides, 
so that a multinucleated mass is produced — the “ spermato- 
gemme this becomes segmented, and each segment develops 
into a spermatozoon. The cell at the base, or spermatogonium, 
retains its connection with the spermatozoa until their develop- 
ment is completed. 
Somewhat similar accounts have been given in 1880 hv 
Meyer, in the 'Memoirs of the St. Petersburgh Academie/ 
and by Brissand in the £ Archives de Physiologie.’ 
Helmann in 1879, and W. Krause in 1881, agree with 
Lavalette St. George in considering the supporting cell and 
the spermatozoa to be derived from the same parent cell, but 
agree with Sertoli that the germinative cells of the outer layer 
are the progenitors of the spermatozoa. They consider that 
one of the nuclei of the spermatogemme migrates towards the 
wall of the tubule, passing between the cells of the second 
layer to become embedded in the outer layer upon the basement 
membrane, and that this nucleus, retaining its connection with 
the spermatogemme and increasing in size, becomes the sup- 
porting nucleus, while the spermatogemme develops into a 
group of spermatozoa ; so that, according to this view, there 
are no follicular cells in the tubules. I myself held for some 
time such an opinion as this upon the relation between the 
spermatozoa and the supporting cell, and have already ex- 
plained at some length why I felt obliged to give it up. 
Klein, in the 'Atlas of Histology/ in 1881, gives an account 
of the development of spermatozoa in the dog and some other 
