118 UNIVERSITY OF WISCONSIN STUDIES 
Caractéres biologiques (Blanchetiere et Gougerot). 
Fait fermenter la saccharose. Fait fermenter la lactose. 
Ne semble pas faire ferment- Ne semble pas faire ferment- 
er la lactose, ete. er la saccharose, etc. 
Matruchot has stated the differences more in detail but 
since all the essential points are covered by the above outline 
it will not be necessary to state them again. I shall take up 
these points in order and attempt to analyze them in the light 
of data from both American and French sources. 
First, as to the optimum temperature for growth, Schenck 
states that for his organism it was between 20°C. and 387° C. 
Hektoen says it would seem to be about 37° C. Growth is 
much slower at 20° C. My own experiments have not con- 
vinced me that there is any appreciable or constant difference 
in optimum growth temperature between Sp. schencku and 
Sp. beurmanni. Slight differences are often: observable be- 
tween various strains of sporotricha. In growing many cul- 
tures side by side, including the original Sp. schencku, growth 
was most rapid and most abundant at temperatures from 
28° C. to 32° C. Variation in optimum growth temperatures 
is common in fungus organisms of this type. They are not 
delicate in this respect and small differences should not be 
unduly emphasized as differentiating features. 
In the outline quoted above de Beurmann and Gougerot 
have next emphasized certain points concerning the ma- 
croscopie characters on special media of the cultures which 
in their opinion are important in differentiation. These points 
center chiefly round the fact that sporotricha generally are 
especially prone to change and modify their eultural prop- 
erties on artificial media, a character referred to as pleomor- 
phism. This is so important and so much has been made of 
cultural differences in distinguishing Np. schenckii and Sp. 
bewrmanni that I must discuss it somewhat in detail. 
First, the colonies may in a great variety of wavs alter 
their pigmentation, the tints changing through various shades 
of brown and black; portions or all of the culture may be pure 
white. These changes may or may not be permanent. I 
