Dr. Basquet has just published in the Annales de Dermatologie a memoir in which he recalls the observations of Draper, of Anderson, of Quincke, of the Lyon's school, which prove that the murides (rats and mice) furnish the first soil on which grows the still unknown fungus which produces favus. Upon these animals it begins to modify its mycelial characters and to generate the form which in cultures becomes the achorion arloini. From the skin of the mouse which is free from sudoriparous glands and of which the reaction is probably very feebly acid, and where the temperature is but little elevated the achorion passes to the cat, the dog, the rabbit, the ox, the horse, the fowl and to man whose external temperature is more elevated and has a much more acid reaction. In this passage from one animal to another the fungus changes its aspect and after a more or less prolonged sojourn in the new medium living where it finds itself, it takes on a distinct form according to its surroundings. The author publishes a report of this opinion, the case of a young girl of nineteen years, affected with a circinate eruption upon the dorsal aspect of the right hand, upon which he found the achorion arloini—that is to say the achorion of the mouse. This young girl had been contaminated by mice affected by favus which she had touched. The fungus having only been for a short time in process of evolution, her skin had not had time to undergo transformation. All these researches require much further study in order to be definitely admitted.
J Cutan Genito-Urin Dis.
The Origin of Favus. Arch Dermatol. 1993;129(3):398. doi:10.1001/archderm.1993.01680240144037