CHAPTER XLI. 



DISEASES OF THE SKIN — continued. 



FAVUS, OR HONEYCOMB RING-WORM — EXPERIMENTS OF GRUBY — THE 

 ACHORION SCHONLEINII THE YELLOW CRUST DUE TO THE EXU- 

 DATION TRANSMISSIBILITY OF THE DISEASE FROM ANIMALS TO 



MAN, AND VICE VERSA TINEA CIRCINATUS THE TRICOPHYTON 



DISCOVERED BY MALMSTEN IDENTITY OF FAVUS AND TINEA 



CIRCINATUS LETTER FROM MR. M'GILLIVRAY OF BANFF 



TREATMENT OF RING-WORM. 



DISEASES DUE TO VEGETABLE PARASITES — DERMATOPHYTA. 



The vegetable parasites, or epiphytes, which cause diseases of 

 the skin, are microscopic growths belonging to the lowest class 

 of vegetable existence, namely, the fungi, cryptogamia. Most of 

 them are composed of simple sporules, germs, or cells, placed 

 side by side, or end to end. 



Two forms of skin diseases traceable to vegetable parasites 

 are now pretty well understood ; they are the tinea tonsurans, 

 also called tinea tondens or ring- worm, and favus, honeycomb 

 ring-worm, or scald-bead. 



FAVUS, OR HONEYCOMB RING-WORM. 



This is a disease little known in this country, and is described 

 as a fungus parasitic disease, composed of cup-shaped scabs, 

 sometimes distinct and separate, at other times indistinct or 

 confluent. These fungi are capable of being implanted from one 

 animal to another, from man to animals, and animals to man ; 

 and Gruby tried the effects of the inoculation of the parasite on 

 vegetables, and succeeded, by inoculating the bark of an oak- 

 tr^e, in getting a favus-cup identical with that which grows on 

 the heads of children. 



