CHAPTER XXXIV. 



THE PATHOGENIC FUNGI AND YEASTS (BLASTOMYCETES) DIS- 

 EASES DUE TO MICRO-ORGANISMS NOT YET IDENTIFIED. 



The Fungi. 



MOST of the fungi are not pathogenic and interest us merely as organ- 

 isms which are apt to infect our bacteriological media. Some are, 

 however, true parasites, and already we know that ringworm, favus, 

 thrush, and pityriasis versicolor are caused by fungi. Only those causing 

 ringworm, favus, pityriasis, and soor will be touched on. 



Trichophyton (Ringworm Fungus). 



Ringworm of the body or hairless parts of the skin, tinea circinata, 

 and ringworm of the hairy parts, tinea tonsurans and tinea barbce or 

 tinea sycosis, are due to the fungus trichophyton, discovered by Gruby 

 in the human hair, and between the epidermal cells by Hebra, and 

 obtained in free cultures by gravity. 



FIG. 135 



Hair riddled with ringworm fungus. Megalosporon variety. 



According to Sabouraud, whose conclusions are based on an exten- 

 sive series of microscopic examinations of cases of tinea in man and 

 animals, of cultivation in artificial media, and of inoculation on man 

 and animals, there are two distinct types of the fungus trichophyton 

 causing ringworm in man one with small spores (2 to 3 mm.) which 

 he calls "T. microsporon," and one with large spores (7 to 8 mm.) 

 which he calls "T. megalosporon." They differ in their mode of growth 



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