TRIOHOPHYTONEAE 



465 



The geographic distribution of these organisms is very interesting, al- 

 though not so carefully studied as to allow us to make very satisfactory 

 generalizations. Much suggestive data accumulated before 1928 have been sum- 

 marized by Alexander & Bruhns, but so many records are based on a com- 

 paratively small number of cases or over such a short period of time, often 

 in the presence of an epidemic which increases greatly the number of cases 

 due to one organism, that the conclusions should be regarded as tentative. For 

 example, cases of Epidermophyton infection seem to have been comparatively 

 rare or at least rarely diagnosed and cultivated in Europe before the war and 

 have not increased very notably since, while since the war in America it has been 

 recognized in increasing frequency until it appears to attack very large per- 

 centages in certain portions of the population. Whether this should be consid- 

 ered an importation with the returned soldiers, or whether it represents increas- 

 ing diagnostic skill among dermatologists and other physicians is difficult to 

 state. A study of records of the Massachusetts General Hospital over the pres- 

 ent century shows that diagnoses of mycoses of the glabrous skin have increased 

 greatly, while eczema has diminished by about the same proportion. It would 

 seem that there has been increased skill in recognizing the fungus nature of the 

 disease rather than an actual increase in number of fungus infections. On the 

 other hand, the general impression of several of the older dermatologists seems 

 to be that Epidermophyton infections increased greatly after the war. 



Data on the relation of infection by a given fungus to a given race are 

 even less accurate, and much rarer. For example, the only cases of Micro- 

 sponim ferrugineum infection are reported on Japanese and Chinese, but I 

 know of no inoculation experiments with this fungus on members of other 

 races. Again, FavotricJiophyton violaceum seems confined to the Semitic race 

 or to populations where there has been a large admixture of Semitic blood, 

 but there are very few statistics to prove this point and I know of no inocu- 

 lation work. In Algeria and Tunis it is confined to the Arab population and 

 Italian immigrants. In the former Kussian Empire it appears in surveys only 

 in regions with large Jewish populations. It also occurs quite frequently in 

 Italy, especially in the southern part. Here I know of no statistics in which 

 racial characteristics are recorded, but it should be remembered that this 

 region has been invaded several times by Semitic peoples. Similarly, it is 

 more common in the cities of southern France than farther north. In the 

 United States our experience indicates that it is largely confined to persons 

 of Russian-Jewish extraction. It occurs occasionally in Brazil, Uruguay, and 

 Argentina, in some cases being mentioned as occurring only on Jews. The 

 closely related species, F. gJahrum (Catanei 1929, 1930, 1931, 1933), has ap- 

 proximately the same distribution, but is usually rarer. In Algeria most of 

 the statistics show that in the indigenous population F. glahnim is slightly more 

 common, while in the Jewish population F. violaceum is the more common. The 

 percentage of tinea and favus cases is much larger among the native population. 



The changes in the dermatophyte flora of Europe since the war have been 

 remarked by several investigators. Several species, such as Microsporum 



