24 



Scientific Proceedings (77). 



Macroscopically and microscopically these cultures appeared in 

 every respect like yeast or saccharomyces. 



The " blastomycotic " pleomorphism has been observed by 

 Gougerot for the Sporotrichum beurmanni, but has never been 

 described for the American strains. When transplanted on very 

 moist and soft agar, I repeatedly noticed, for at least three to four 

 days, the yeast-like character of some human strains, isolated 

 from cases in North America, but such cultures always returned 

 to the typical growth within ten days. 



The tendency of a recently isolated strain of sporothrix to 

 revert to its parasitic pleomorphism under unfavorable conditions 

 (moisture, absence of oxygen, and carbohydrates) appears to be a 

 characteristic of the European as well as of the American types, 

 and clearly proves their close botanical relationship with the 

 "blastomyces." 



Serologic tests 1 have previously shown that complement fixa- 

 tion is regularly obtained with sera of infected or immunized 

 animals when various yeasts are used as antigens. 



1 Amer. Jour. Trop. Diseases and Preventive Medicine, 1915, III, 144. 



