RINGWORM 477 



removed by forceps and placed on a sterile glass slide. 

 The aerial portion of the hair is then cut away by means 

 of a sterile scalpel, and the diseased portion is divided into 

 small fragments. These can be picked up with a moistened 

 platinum needle and transferred to the culture media, 

 preferably beer-wort agar. In some cases a pure culture 

 is thus obtained, but in others further treatment is neces- 

 sary. When the Trichophyton or Microsporon has thrown 

 up its aerial hyphaa the plug of wool is removed from the 

 tube and the mouth well flamed ; the tube is then held 

 inverted over a Petri dish containing solidified maltose 

 agar. A sharp tap or two is given to the tube, sufficient 

 to cause the spores to drop, and the dish is re-covered. 

 A growth of the organism from single isolated spores thus 

 ensues, and pure cultures can be obtained (Blaxall). 



The various forms of the ringworm fungi can be differen- 

 tiated by cultures, but it is necessary when comparing them 

 to employ media of identical composition, because slight 

 differences in the latter are liable to induce marked changes 

 in the characters of the cultures. A favourite medium, 

 used by Sabouraud and by Blaxall, is maltose agar : 



Peptone 0*5 grm. 



Maltose 3-8 grm. 



Agar-agar 1-3 grm. 



Water 100 c.c. 



Blaxall found that different samples of maltose materially 

 influenced the characters of the cultures. 



Characters of the cultures. Cultures are incubated at 

 30 C. The colonies of the Microsporon do not show any 

 growth until about the seventh day ; little white downy 

 tufts then appear. The fully developed growth on maltose 

 agar forms a large white downy patch with a small central 

 boss ; on potato white downy patches appear with brown 

 discoloration. 



