SPOROTKICHOSIS 543 



are Gram-positive. Mycelial formation does not occur in the 

 tissues except occasionally in the most superficial parts of an 

 ulcerating lesion. If a drop of pus be placed on the glass of an 

 agar slope just above the condensation water, the sprouting of 

 a mycelium from the spores may be directly observed with the 

 microscope. The organism, which is generally known as the 

 Sporotrichon beurmanni, grows readily on any ordinary medium 

 (gelatin, agar, potato), but is best studied on Sabouraud's 

 medium. Two sets of media 

 should be inoculated one 

 incubated at 37 C. and the 

 other at room temperature. 

 On the latter, after about 

 forty-eight hours, somewhat 

 fluffy, snowflake-like, white 

 points appear which gradu- 

 ally become brown, and when 

 growing in mass present a 

 heaped-up convoluted growth. 

 The morphology of the organ- 

 ism is best studied in hang- 

 ing-drop preparations made 

 with agar. From a spore a 

 mycelial thread about 1 /A in 

 thickness, irregularly septate, 

 and often containing fine 

 granules, sprouts off. Lateral 

 branches arise and fresh spore 

 formation is soon observed. 



These usually develop in , 



, i j XM * /-cv FIG. 170. Film from agar culture o* 



whorls round a filament (* ig. s por otrichon beurmanni grown at 37 



169), but sometimes the C. for ten days. Gram's stain. x!025 



process occurs all along a Note large circular bodies with spores 



. e , , sprouting off ; also a few sausage-shaped 



filament. Sometimes, in the elements 



course of a filament, large 



circular elements, 5-6 p in diameter, resembling the zygospores 

 of Mucoracese are seen, and these sometimes contain groups of 

 spore-like bodies. The free growth of the organism depends on 

 conditions of moisture and temperature, and where these are 

 unfavourable, instead of mycelial formation being observed, the 

 spores may enlarge to three or four times their ordinary size 

 and then give off circles of fresh spores (Fig. 170). Under a 

 low power of the microscope, mycelial colonies have a stellate 

 appearance with a very freely spiked edge. The organism 



