THE PATHOGENIC FUNGI 987 



from systemic infections was impressed with the effect of the tem- 

 perature of incubation on the morphology of the organism. All 

 of his strains grown in the incubator tended to multiply by budding, 

 while at room temperature all were filamentous, and two produced 

 aerial hyphae. 



Pathogenicity. All strains which have been tested have proved 

 pathogenic for laboratory animals. White mice seem the most 

 susceptible. 



Classification. Cultures from the various cases have shown little uni- 

 formity. It is impossible to be certain that they represent distinct species 

 as they are somewhat pleomorphic and change their morphology with varying 

 cultural conditions and after long preservation on artificial media. 



The most serious attempt to systematize their varying char- 

 acteristics is that of Ricketts. 13 He considered the seventeen strains 

 on which he based his report all to be closely related species of one 

 genus. He described three main types under which in spite of 

 minor differences he grouped the various strains. 



His classification, is not however, satisfactory. Stober 14 has observed 

 the three types of agar growth to occur successively in the same strain. 



A definite classification of these organisms is as yet impossible but there 



seem to be two types which the various strains more or less closely resemble. 



I. The fermenting type described by Busse and called Cryptococcus hominis 



by Vuillemin, Brumpt and Castellani. These organisms resemble the 



true yeasts in their morphology and zymogenic properties. 



II. The non-fermenting type described by Gilchrist and called Cryptococcus 



Gilchristi by Vuillemin, Cryptococcus dermatitidis by Castellani and 



Mycoderma dermatitis by Brumpt. These types usually produce 



mycelium and reproduce by means of thallospores and conidia. They 



are related to the sporothrices and trichophyta described below. There 



is no correlation between the type of organism and the type of 



lesion it produces. 



COOCIDIOIDAL GRANULOMA 



There is a group of cases resembling closely systemic blastomy- 

 cosis, the first observation of which was that of Wernicke and 

 Posadas. 15 



"Eicketts, J. Med. Res., 1901, vi, 373. 



14 Stober, Arch. Int. Med., 1914, xiii, 509. 



15 Wernicke , E., Centralbl. f. Bakteriol., I, 1892, xii, 859. 



