578 A MANUAL OF BACTERIOLOGY 



Hairs, after treatment with ether for half an hour, may be 

 stained by the following method : 



(1) Stain in anilin -gentian violet for one to two minutes, and 

 blot. 



(2) Treat with Gram's iodine solution for one to two minutes, 

 and blot. 



(3) Decolorise carefully (watching microscopically) with anilin 

 oil containing 1 per cent, of hydrochloric acid. 



(4) Treat with anilin oil and then with anilin oil and xylol. 



(5) Clear in xylol, and mount in Canada balsam. 

 ERYTHRASMA. Due to infection with a fungus (Microsporon 



minutissimum), very difficult to cultivate, which occurs as 

 extremely fine interlacing jointed filaments without branches. 



FAVUS. Favus is due to a fungus discovered by Schoenlein 

 in 1839 the Achorion ScJioerileinii. It is seen as a mycelial 

 growth with spores in the patches. The organism grows well 

 on maltose agar, forming fluffy, woolly, moss-like colonies with 

 radiating outgrowths, first grey and then yellowish. It occurs on 

 mice and other animals. 



DHOBIE ITCH. Castellani has isolated three trichophyton-like 

 organisms in this disease. 



PITYRIASIS ALBA. In this disease Unna's " bottle bacillus " 

 is invariably present. It occurs as large round or oval bodies like 

 yeast-cells, which may occasionally show budding. 



PITYRIASIS VERSICOLOR. In the epidermal scales of this skin 

 affection a fungoid organism (Microsporon furfur) is present. It 

 occurs as short and thick curved hyphse, between which are 

 masses of large coarse spores. Cultures can be obtained only on 

 special media, such as epidermin agar. 



PINTA. A skin disease met with in South America. In the 

 scales short mycelial filaments with large (8-12 /i) spores are 

 seen. Various organisms have been cultivated belonging to the 

 genera Penicillium and Aspergillus. 



PIEDRA. A disease of the hairs met with in South America. 

 The nodosities on the hairs are composed of masses of very large 

 refractile spores. The fungus is supposed to be a Trichosporium. 



TINEA IMBRICATA. A tropical ringworm due to Endodermo- 

 phyton concentricum. The mycelial threads are long and spores 

 irregular. 



