118 UNIVERSITY OF WISCONSIN STUDIES 



Caracteres biologiques (Blanchetiere et Gougerot). 



Fait fermenter la saccharose. Fait fermenter la lactose. 



Ne semble pas t'aire ferment- Ne semble pas faire ferment- 

 er la lactose, etc. 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 20C. and 37 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. schenckii 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. schenckii, 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- 

 croscopic 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 cultural 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 Sp. schenckii and Sp. 

 beurmanni that I must discuss it somewhat in detail. 



First, the colonies may in a great variety of ways 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 



