642 PATHOGENIC MICROORGANISMS 



prolonged cultivation. The etiological relationship of Ashford's 

 Monilia to Sprue is not as yet generally accepted. 



Favus (Achorion Schoenleinii) . Favus is a disease attacking chiefly 

 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 re- 

 sistant 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 indented crust is spoken of as a scutulum. When such a scu- 

 tulum is removed 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 center of the 

 scutulum is found to be made 

 up chiefly of small doubly-con- 

 toured spores, which are irregu- 

 larly oval or round, and may be 

 arranged in chains, lying scat- 

 tered among an extremely dense 

 FIG. 151. THRUSH. Oi'dium albicans, , , /> ,. 



uBstained. (After Zettnow.) mesh work of fine mycehal 



threads. Toward the periphery 



of the scutulum, the spores are less numerous and the looser arrange- 

 ment 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 * believes 

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

 another, owing to the fact that selective cultivation has succeeded in 

 altering many of the characteristics displayed by many of the strains. 

 The same observer recommends the following method for obtaining 

 pure cultures of this microorganism. As much of the material as 

 can be conveniently obtained is gently rubbed up in a sterile mortar 

 with fine sand or infusorial earth. The triturated material is then 

 inoculated into fluid agar and plates are poured. 



Ordinary streaked plates upon agar may also be used with success 



with material directly from the centers of scutula. 



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



