MICROSCOPICAL DIAGNOSIS. 



stumpy hairs should be placed on a glass-slide, covered and 



treated with liquor potassae. 



Tinea Sycosis. Barber's itch. The hairs are 

 dry, swollen, brittle and many times twisted. 

 They are loose and may be extracted without 

 pain. The fungus penetrates into the hair fol- 

 licle and affects chiefly the roots of the hair. 

 The parasite differs but little from that found 

 in tinea tonsurans only perhaps there is rela- 

 tively more mycelium in tinea sycosis. The 

 spores, however, still predominate in this affec- 

 tion. 



Tinea Versicolar. This disease is caused by 

 a vegetable parasite, known as microsporon fur- 



Fig. 20. ^Demodex f lir ' The m y celium of this fungus is composed 

 Folliculorum. of short, slender threads, that may be either 

 timpty, or that may contain a few spores and granules. It is 

 not uncommon to find a single spore on the end of a thread 

 of the mycelium. The threads vary considerably in form, being 

 found jointed; twisted, straight, or crooked an* wavy. The 

 spores are small and irregular in shape as in achorion Schon- 

 leinii. They have a tendency to aggregate in groups. These 

 masses are very characteristic, as they are not found in any 

 of the other vegetable parasites. Free spores are met with 

 everywhere. The growth is very luxuriant and there is no 

 difficulty in detecting it with the usual magnifying power. A 

 few of the epidermal scales are placed upon a slide, covered, 

 and treated with a drop of liquor potassae. 



Animal Parasites. The animal parasites are so readily de- 

 tected by the unaided eye that it is scarcely necessary to 

 mention them. The itch mite is the least liable to be de- 

 tected, but this is easily seen' with the microscope. On turn- 

 ing one out of the pustules from between the fingers with the 

 points o f very fine needles and placing it under the micros- 

 cope the minute animal sarcoptes scabiei is seen. It gives rise 

 to the disease known as scabies. 



The Demodex Folliculorum (fig. 20) inhabits the sebaceous fol- 

 licles of healthy skin, hence gives rise to ro trouble. If one of the 

 follicles about the nose or forehead be squeezed rather hard, 



