106 STUDY AND IDENTIFICATION OF MOULDS. 



is affected we have a dark violet color. Deeper 

 involvement gives red spots. 



Hyphomycetes. In this order are grouped certain genera which 



cannot properly be assigned to any of the other orders. 



Discomyces bovis. This is the well-known ray fungus, the cause of 

 actinomycosis. In man it is at times found in chronic sup- 

 purative conditions attended with much granulation tissue. 

 Such pus may show 7 small yellow-gray granules about the 

 size of a pin's head. When spread out between two slides 

 the central portion shows a net-work of mycelium with bulbous 

 thread-like rays going to the periphery. The " clubs" at the 

 periphery are degenerate structures and do not stain by Gram. 

 The central mycelium is Gram positive. This mould is 

 essentially an anaerobe and should be cultivated in a deep 

 glucose agar stab. It may also be cultivated in bouillon. 

 In this it grows at bottom. Growth is dry and chalky. 

 In diagnosis look for the little granules. Curetting of the 

 sinuses may give the "ray fungus" when they are not found 

 free in the pus. 



Discomyces madurae. This is a ray fungus found in the yellow "fish- 

 roe" granules of madura foot. It is strictly aerobic in 

 cultures, thus differing from actinomycosis. For diagnosis 

 proceed as for D. bovis. 



Madurella mycetomi. This is the cause of the black "gunpowder" 

 granules of madura foot. It is a mycelial mass with rather 

 oval shaped swollen segments. It is at times cultivable on 

 potato and agar as felted masses of gray growth, which later 

 becomes almost black. 



Malassezia furfur. This is the fungus of Tinea versicolor. It is 

 common both in temperate and in tropical climates. It is 

 characterized by dirty yellow spots about covered parts 

 of the body. Scrapings show a profusion of mycelial 

 threads and interspersed spores. It is very difficult to 

 cultivate. 



Microsporoides minutissimus. This is generally considered as the 



