786 THOS. H. MONTGOMERY, JR. 
alizarine method, has come to be replaced by the criterion of 
their genetic origin and fate.!® 
Here I propose to discuss the mitochondria merely with rela- 
tion to their mode of origin, mode of division and history during 
the spermatogenesis, with reference especially to the phenomena 
in Euschistus. In Euschistus the spermatogonia contain a few 
granules that never stain as intensely as the mitochondria of the 
spermatocytes, and are never in the form of threads; it was not 
determined whether these are mitochondria or idiozome remains, 
but there is more indication of the latter origin. In various 
other animals, also, they appear to be few or absent in spermato- 
gonia, though described for such cells by Meves (’00, ’07), Gérard 
(09), Giglio-Tos (’08), Wassilieff (07), Lams (09), Dingler (’10), 
Holmgren (’02), Bouin (’05), Otte (07) and the Schreiners (’05)?° 
They are also few or absent in oogonia. But in Euschistus and 
other objects they are always much more abundant in the growth 
period of the germ cells, and this is certainly the time of their 
chief elaboration, a point noted also by Buchner (710). This 
is a rather important matter, and easily proven by comparing the 
. large mass of them in spermatocytes with their mass in spermato- 
gonia. The mitochondria thus have their main period of growth 
and multiplication in the growth period of spermatocytes and 
oocytes. Their later history, in maturer germ cells, embryonic 
and tissue cells is in general one of distribution and differentiation. 
This leads us to the question of their origin in the growth 
period. Some writers consider them essentially cytoplasmic 
structures, with no genetic relations to the nucleus; such are 
Meves, Duesberg, Bouin, Korotneff, Dingler, while Vejdovsky 
(and his results apply only to oocytes) regards them as portions 
19 Probably many of the bodies described in spermatocytes as yolk globules will 
prove to be mitochondria, as well as many bodies previously confused with idio- 
zomes. However, Gross has distinguished in Pyrrhocoris yolk granules from mito- 
chondria. a 
20 The large compact masses in the distal ends of spermatogonia, shown by 
Giglio-Tos in his fig. 1 and regarded by him as mitochondria, are clearly not such 
but mitosomes; he was misled by their taking the Benda stain, which shows how 
little service this stain is as a diagnostic. 
