546 



PATHOGENIC FUNGI 



fine granules, sprouts off. Lateral branches arise and fresh 

 spore formation is soon observed. These usually develop in 

 whorls round a filament (Fig. 170), but sometimes the process 

 occurs all along a filament. Sometimes, in the course of a fila- 

 ment, large circular elements, 5-6 /x 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 



--« cm 



Pig. 170.- 



-Edge of, living colony of Sporotrichon beurmanni on agar 

 hanging-drop, five days at 22° C. X 200. 



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. 171). 

 Under a low power of the microscope, mycelial colonies have 

 a stellate appearance with a very freely spiked edge. The 

 organism manifests considerable vitality under saprophytic con- 

 ditions, as might be expected from the widespread distribution 

 in nature of allied members of the group and even,, it is said, of 

 the Sporotrichon beurmanni. • The organism in artificial cultures 

 is pathogenic when injected subcutaneously in mice, rats, dogs, 



