276 GERM-CELL CYCLE IN ANIMALS 
the nucleus; these bodies have been given various 
names such as sphérules (Kunstler, 1882), cytomi- 
crosomes (La Valette St. George, 1886), bioblasts 
(Altmann, 1890), and ergastoplasm (Bouin, 1898). 
In 1897 and 1898 Benda noticed the constant pres- 
ence of certain granules in the male germ cells of a 
number of vertebrates and was able to trace their 
history from the spermatogonia until they formed the 
spiral filament in the tail of the spermatozoa. These 
observations were extended the following year 
(1899) so as to include all stages in the development 
of the eggs and spermatozoa of many vertebrates 
and invertebrates and also various tissue cells such 
as striated muscle-fibers, leucocytes, marrow-cells, 
etc. This work attracted wide attention chiefly 
for two reasons: (1) the history of the granules 
was carefully worked out and the various stages 
accurately described, and (2) special, rather com- 
plicated, staining methods were devised which were 
supposed to color the mitochondria so that they 
could be distinguished from all other cell inclusions. 
From 1899 until the present time an ever increasing 
number of investigators have attacked the problems 
presented by the mitochondria, or referred to these 
structures incidentally when working upon other his- 
tological or cytological problems. The study of mito- 
chondria received its greatest impetus, however, 
in 1908, when Meves published a paper on these 
structures in the chick embryo entitled ‘‘Die Chon- 
driosomen als Trager erblicher Anlagen.” In this 
paper the chick embryo is described from the fifteen- 
