HYPHOMYCETES 



641 



the hairy portions of the body of man and some domestic animals. 

 In man, it is found most frequently in undernourished children upon the 

 scalp. It is a disease of extremely chronic course and is very resistant 

 to treatment. Beginning as a small erythematous spot, it soon develops 

 into small sulphur-yellow cupped crusts, which are placed usually about 

 the base of a hair. These may spread and coalesce. The small inden- 

 tated crust is spoken of as a scutulum. When such a scutulum is re- 

 moved and examined under a microscope, teased out in a few drops of 

 strong sodium hydrate solution (20 per cent), the incitant of the disease 

 may be easily recognized and studied. In such a preparation the cen- 



FIG. 150. ASFERGILLUS * GLAUcus. m. Mycelial threads, s. Sterigmata. 

 r. Ascospore. p. Germinating conidium. A . Ascus. (After de Bary .) 



ter of the scutulum is found to be made up chiefly of small doubly- 

 contoured spores which are irregularly oval or round, and may be ar- 

 ranged in chains, lying scattered among an extremely dense meshwork 

 of fine mycelial threads. Toward the periphery of the scutulum, the 

 spores are less numerous and the looser arrangement of the meshwork 

 permits us to distinguish distinct filaments of mycelia which give 

 off hyphae, the ends of which are often swollen into small knobs. The 

 interior of the scutulum usually contains a pure culture of the fungus. 



Many varieties of achorion have been described, but Plaut 1 believes 

 that, at the present time, it is not possible to separate these from one 



1 Plaid, in Kolle und Wassermann's "Handbuch," I. 



