464 
Keene. — Cytological Studies of the 
origin. That these are not products of the disorganizing nuclei seems 
evident from their early structure and staining reactions. At first they 
stain lightly violet. They are generally globular in shape, although they 
vary somewhat, and are coarsely reticulate. They stand out as distinct 
individual structures. Many originate near the periphery of the zygospore, 
but others are found through the central portion during the period of zona- 
tion. These new cytoplasmic bodies are confusing at first, and only 
a careful study of their function and fate has placed them as definite cell 
structures. The structures described by Leger under the name of { spheres 
embryogenes ’ are most certainly identical with these bodies. Dangeard 
described them as c chromatic corpuscles ’, but did not study them closely, 
and arrived at no conclusions as to their function, apart from comparing 
them to the coenocentra of Stevens. 
That these bodies are not nuclei is evident upon a close study of their 
structure, and is more forcibly emphasized by their subsequent behaviour. 
They gradually increase in size and number (PI. XXXVI, Figs. 10, 10 b), 
as many as forty having been counted in one section of a zygospore cut at 
10 /x. Fusions occur between them without reference to size or number. 
These fusions seem to be due to the rapid increase in size of the bodies, 
which causes a coalescence. 
As these structures enlarge, they show a more definite organization. 
Earlier they appear much as if they were vacuoles filled with a bluish 
staining substance, and only the highest powers of magnification and 
careful staining bring out their reticulate nature. Later, however, they 
gradually lose their coarse reticulation, becoming sponge-like with a denser 
centre (PI. XXXVI, Fig. 10 b). In no cases, under various killing reagents, 
stains, and in careful serial sections, could anything that resembled chro- 
matin or a nucleolus be detected within these bodies. In no instances 
furthermore, were the small previously described nuclei found within these 
structures, but, in all cases, the nuclei can be seen in meshes of the proto- 
plasm between these structures and the vacuoles which are also numerous 
at this time (PI. XXXVI, Figs. 9, 10). 
These structures continue to enlarge and fuse until, in the zygospores 
taken from cultures at the end of six weeks, there appears from one to 
three of these bodies (PI. XXXVI, Fig. 11). Through tests with osmic acid 
and chloroform with fresh material, it is found that, from their first appearance, 
these plastid-like bodies are associated with the formation of oil. In fresh 
material, they appear as large globules, due to the fact that they are com- 
pletely saturated with oil, to the point even that if slightly pressed the oil 
exudes in a large globule or many small ones. This oil is readily soluble 
in chloroform. The oil is not very refractive and is amber coloured. It 
assumes the shape of the plastid-like body, and is not always in the form 
of a definite rounded globule. 
