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[POPULAR SCIENCE REVIEW. 
■mycetes , and the Mucors belong to another family, the Pliyso- 
mycetes. We entertain no doubt whatever that the Mucor , to 
which we have alluded as g'rowing on box-leaves, intermixed 
with Penicillium roseum , is no other than the higher and 
more complete form of that species, and that the Penicillium 
is only its conidiiferous state. The presumption in this case is 
strong, and not so open to doubt as it would be did not ana- 
logy render it so extremely probable that such is the case, 
apart from the fact of both forms springing from the same 
mass of mycelium. In such minute and delicate structures it 
is very difficult to manipulate the specimens so as to arrive at 
positive evidence. If a filament of mycelium could be isolated 
successfully, and a fertile thread, bearing the fruit of both forms, 
-could be traced from the same individual mycelium thread, 
the evidence would be conclusive. In default of such conclu- 
sive evidence, we are compelled to rest with the assumption 
until further researches enable us to record the assumption as 
fact. 
In Lewis’s recent “Report on Microscopic Objects found in 
Cholera Evacuations” (Calcutta, 1870), a similar instance of 
presumed dimorphism between precisely the same genera is 
thus recorded. “ On a preparation preserved in a moist chamber 
on the third day a white speck was seen in the surface consist- 
ing of innumerable 4 yeast ’ cells with some filaments, branch- 
ing in all directions. On the fourth day tufts of Penicillium 
had developed — two varieties, P. glccucum and P. viride. This 
continued until the ninth day, when a few of the filaments 
springing up in the midst of the Penicillium were tipped with a 
■dew-drop like dilatation, excessively delicate — a mere distended 
pellicle. In some cases they seemed to be derived from the 
same filament as others bearing the ordinary branching spores 
of Penicillium , but of this I could not be positive. This kind 
of fructification increased rapidly, and on the fourteenth day 
■spores had undoubtedly developed within the pellicle, just as 
had been observed in a previous cultivation, precisely similar 
revolving movements being also manifested.” Here we have 
another example of a Mucor developed from a Penicillium , and 
one observation strengthens and confirms the other. 
Before entering upon the details of the second apparent 
polymorphism, it may be as well to give some particulars of 
the circumstances under which the fungi appeared. It was 
our fortune — good fortune as far as this investigation is con- 
cerned — to have a portion of wall in our dwelling persistently 
damp for some months ; it was close to a cistern that became 
leaky. The wall was papered with “ marbled ” paper, and 
varnished. At first there was for some time — perhaps months 
- — nothing worthy of observation except a damp wall ; decidedly 
