Baird—History of Phycomyces Nitens (Agardh) Kunze. 373 
readily with safranin. This is undoubtedly the body seen and de¬ 
scribed by many writers as the nucleole. The vesicle that I have 
called a vacuole associated with one or more chromatin bodies 
seems to have been considered by others the nucleoplasm. 
As I interpret the structure of the protoplasm of Phycomyces 
and Rhizopus, the homogeneous body is nucleus; it has the general 
nature of chromatin in that it stains readily and is present in all 
stages in the life history of these fungi. 
Single masses of this chromatin may exist unassociated with 
others, as in the spores, where the single body appears to have orig¬ 
inated from the reassembling of two or more small bodies that had 
previously been formed by the division of a single chromatin body, 
and in the vegetative hyphae, where individual bodies have be¬ 
come disassociated from others by the obliteration of a vacuole that 
previously had been active in bringing about division. Most fre¬ 
quently several nuclei are associated with a vacuole and these 
nuclei may or may not be connected by slender strands of proto¬ 
plasm other than the vacuolar membrane. A vacuole thus asso¬ 
ciated with one or several nuclei seems to have been formed within 
the chromatin mass. Usually, the vacuole grows in such a way as 
to rearrange the chromatin substance into several bodies around 
its periphery. At other times, as it grows, the vacuole forms eccen¬ 
trically in the chromatin body, leaving most of the chromatin un¬ 
disturbed. 
Although it has been observed that slimy cytoplasm seems to be 
formed in the immediate vicinity of the nuclei, as in the germinat¬ 
ing zygospores and in the propagation of the mycelium from aged, 
dried plants, and that at the time this cytoplasm is being formed 
the nuclear vacuoles apparently lose their reserve, one can hardly 
conclude whether the nuclei are active metabolic centers contribut¬ 
ing to this metabolism by forming cytoplasm from the reserve of 
fat outside of the nuclear structures, or whether the food has been 
stored in the nuclear vacuoles, and, later, cytoplasm formed di¬ 
rectly from it. Possibly both the reserve in the nuclear vacuoles 
and the fat outside are used. But it appears evident that the nuclei 
are very intimately associated with the processes that bring about 
the renewed vegetative condition of the protoplasm. 
The nuclei in the mature spores of the sporange are dense, homo¬ 
geneous bodies. When the spore is first formed in the sporange it 
contains several nuclear vacuoles with two or more chromatin 
bodies associated with each. The condition of the nuclei in the 
