546 



MEDICAL MYCOLOGY 



agar, but only half the size, center rust-brown, surrounded by a yellowish 

 zone and a grayish white margin, powdery. 



In the literature available to me, there seems to be very little to separate 

 the following species of this subgenus (except M. orientale) from M. ferrugi- 

 neum; but in the absence of access to the early literature, I have not attempted 

 to reduce them to synonymy. If the references which I have not seen are 

 correctly quoted, probably M. ferrugineum is the oldest name and should be 

 used, although M. japonicum was probably proposed only one or two months 

 later. Regardless of the name used, each author insists that his organism is 

 the commonest dermatophyte in Japan and adjacent regions. 



I 

 I 



Fig. 87. — Microsporuin ferrugineum. (Afier Lang-eron & Milochevitch 1931.) 



As more data become available I suspect that this group will be found 

 to have originated in Mongolia and Turkestan among the nomads in close 

 association with the horse. It seems most closely related to M. equinum, and 

 probably represents a relatively recent adaptation to man in which variation 

 is still abundant and degeneration of sexual processes has begun along with 

 increasing specialization to one host. This degeneration also seems to have 

 begun in M. equinum., but too little cytologic and morphologic work has 

 been done in either group to warrant very definite statements. 



Microsporuin japonicum Dohi & Kambayashi, Jap. Jour. Derm. Urol. 21: 

 433, 1921. 



Microsporum sp. Kambayashi, Jap. Zeitschr. Derm. Urol. 19: 491, 1919. 



