A Rep Mouup. By Raxupru Gitson CurRTISS. 
The mould with which this paper has to deal was first found at Pur- 
due University upon a plate culture which had been exposed to the air. 
It was at first supposed to be a mixture of a mould with a yeast, and this 
idea was a natural one in view of the behavior of the form when grown 
upon gelatine cultures. The characteristics exhibited during growth in 
this way seem to partake both of those ascribed to moulds and those 
which we are accustomed to associate with yeast forms. A mycelium is 
developed first, the early stages of which resemble in their growth those 
of the common moulds, but which soon disappear completely, its place 
being taken by a reddish film which covers the entire surface of the cul- 
ture and which is thickly dotted with red specks. This dotted appearance 
is what gave rise to the supposition that a yeast was present in company 
with the mould, and it was only after a series of attenuated cultures had 
been made from the original plate that the true nature of the growth was 
ascertained. 
It is evident -that in a form whose growth shows such a remarkable 
and abrupt transition from the true mould stage to a yeast-like stage, 
we have a subject for research which should amply repay the most careful 
investigation. As soon as it was determined that both appearances were 
due to the growth of a single mould, cultures were made for the purpose 
of following its life history. 
In fluid cultures the best results have been obtained with wort and 
Pasteur’s solution. On wort kept at room temperature, a growth is ap- 
parent in twenty-four hours, and in forty-eight hours colonies are visible 
throughout the medium as well as covering the surface. 
The peculiar red color is noticeable even in the thinnest portion of the 
growth, that on the surface showing as a pinkish film. This film, when 
broken by the platinum needle for purposes of examination, is found to 
possess a considerable toughness and is difficult to remove from the tube, 
except in large pieces. 
A point which will receive more attention in later investigations is 
that when grown upon sugar solutions, all that portion of the growth 
which is exposed to the air turns black as it ages, while cultures made at 
the same time upon wort retain the characteristic red color. 
The filaments of this mould vary considerably in size, according to 
age, the younger ones having the lesser diameter. They are divided at 
