408 VETERINARY BACTERIOLOGY 



THE GENERA TRICHOPHYTON AND MICROSPORON, ACHORION, 



AND OlDIUM 



The organisms belonging to the two genera, Trichophyton and 

 Microsporon, are frequently included together under the single 

 genus Sporotrichum. The two names, Trichophyton and Micro- 

 sporon, are also used very loosely and interchangeably. A care- 

 ful study of the relationships of the various forms is needed. 



No very clear differentiation of this group from the preceding 

 can be given. 



Organisms belonging to these genera are the cause of many 

 skin and hair infections in man and animals. Pityriasis versicolor, 

 or tinea versicolor, in man is caused by Microsporon furfur 

 (Sporotrichum furfur) ; herpes tonsurans, or ringworm in man and 

 lower animals, by Trichophyton tonsurans. Other species have been 

 described from most of the domestic animals and birds, but they 

 have not in most cases been sufficiently denned and differentiated. 



Trichophyton tonsurans 



Synonyms. The synonymy of the various forms included 

 under this name is almost inextricable. Probably more than one 

 good species is represented. The commoner synonyms are 

 Trichophyton microsporon; Tr. megalosporon ; Microsporon adouini; 

 M. equinum; M. carinum; Sporotrichum tonsurans; S. adouini, and 

 many others. 



Disease Produced. Herpes tonsurans, or ringworm, in man, 

 goat, sheep, pig, horse, cat, and dog. 



The organism was originally described by Gruby in 1842. In 

 its various forms it is world wide in distribution. 



Morphology. The hyphae are relatively slender, septate; the 

 spores are numerous in the hairs and scales. They vary in the 

 different types described from 2 to 8 u in diameter. Chlamydo- 

 spores are produced in artificial media. 



Isolation and Culture. Pure cultures are secured with diffi- 

 culty, as the skin and hair are generally filled with bacteria which 

 overgrow the mold. Krai has suggested pulverizing hairs with 

 fine sand or silicon powder and pouring gelatin plates of various 

 dilutions. Kitt has taken advantage of the resistance of the 

 organism to destruction by alkalies by washing the hairs and 



