SACCHAROMYCETES 553 



bottom, and a new membrane forms. A moderate growth develops 

 in gelatin, but the medium is not liquefied. A slight acidity, but no 

 other visible change, develops in milk cultures. 



The organism is strongly aerobic and grows at room or body tem- 

 perature. At the lower temperature hyphse are more freely formed; 

 at the higher temperature the typical budding predominates and few 

 or no hyphse appear until after several days' incubation. Freezing 

 does not kill Blastomycetes, but an exposure to 60 C. for five minutes 

 is fatal to them. 



Products of Growth. The fermentation reactions are variable. 

 Some strains fail to ferment dextrose or maltose, while others produce 

 gas (CO 2 ) in this medium. On the whole, the fermentative powers 

 of the Blastomycetes are much less than those of the saprophytic 

 yeasts. Toxins and enzymes have not been detected in cultures of 

 the organisms. 



Pathogenesis. Human. The initial lesion, usually cutaneous, is 

 a papule surrounded by an area of hyperemia, which soon becomes a 

 pustule yielding a tenacious pus. The ulceration spreads slowly, dis- 

 charging small amounts of thick, purulent material and surrounded 

 by a red areola in which numerous papules are frequently detectable. 

 As the lesion spreads the older portions of the lesion tend to become 

 cicatrized and to heal. The progress of the disease is very slow, fre- 

 quently requiring years to cover an area of a few square inches. It 

 does not often spread to mucous surfaces, but occasionally metastases 

 occur in the lungs. According to Stober, 1 involvement of bones and 

 metastatic foci in the spleen, liver and kidney have been observed in 

 a few cases. 



Animal Experimentation. Attempts to reproduce blastomycetic 

 infections in dogs, rabbits, guinea-pigs, white rats and mice have 

 been unsuccessful when artificially cultivated organisms from human 

 lesions have been inoculated, although Klein 2 isolated a blastomycete 

 from milk, which produced gelatinous, tumor-like swellings and 

 glandular enlargement when injected subcutaneously into guinea- 

 pigs. Intraperitoneal injections resulted in the formation of firm 

 nodules in the liver, lungs, pancreas, testes, ovaries and intestines. 

 The nodules were composed chiefly of masses of the organisms. Toki- 

 shige 3 and Tartakowsky 4 have isolated organisms belonging to the 



1 Arch. Int. Med., 1914, xiii, 509. 2 Brit. Mod. Jour., 1901, ii, 1. 



3 Centralbl. f. Bakt., 1896, xix, 105. 



4 Die afrikanische Rotz der Pferde, St. Petersburg, 1897. 



