380 MEDICAL MYCOLOGY 



itch, barber's itch, athlete's foot, herpes, favus, or kerion. Nearly- 

 all these fungi grow readily on any common culture medium, but 

 most laboratories employ the standard media of Sabouraud to cul- 

 tivate them. On his "proof medium," containing- sugars, growth 

 is especially luxuriant, and the various species exhibit their char- 

 acteristic cultural aspects. On his "preserving medium," high in 

 peptone and lacking sugars, growth is less rapid in most species, 

 and pleomorphic changes are inhibited. 



There is nothing about their mycelium to enable the worker to 

 differentiate the Trichophytoneae from many fungi commonly 

 encountered in the laboratory. Various hvphal structures and 

 various types of spores which develop in culture are employed, 

 however, to identify and classify the numerous species. They 

 may be briefly described, without reference to any particular 

 genus or species, as follows: 



a. Racket-shaped hyphae. Sabouraud applied the term 

 "raquette cells" to hyphae each of whose cells is of considerablv 

 greater diameter at one end than at the other. When these hyphae 

 occur in series, they have somewhat the appearance of tennis 

 rackets placed end to end. 



b. Terminal clubs. When the apices of hyphae were vari- ' 

 ously enlarged, they were called "terminal clubs" by Sabouraud. 



c. Pectinate hyphae. Hyphae bearing short, denticulate pro- 

 jections along one side are called "pectinate hyphae." Usually this 

 portion of the hypha is curved, and the projections form on the 

 convex surface. If the projections appear as short hyphae, they 

 are termed "nodular organs." 



d. Spiral hyphae. In certain species the terminal hyphae are 

 coiled into a rather tight spiral, making up the so-called "spiral 

 hyphae." These structures are regarded by some workers as com- 

 parable with the hvphal ornamentations on the peridia of certain 

 (A mnoascaceae and as an indication of relationship with this 

 family. 



e. Arthrospores. In the parasitic stage the terminal hyphae 

 become closely segmented, and the segments round up and be- 

 come separate cells. These are the arthrospores, which constitute 

 the sole means of reproduction in nature, if the possible existence 

 of an ascal stage is disregarded. 



f. Chlamydospores. If chlamydospores are classified on the 

 basis of their point of origin, there are three types, terminal, 



