578 WESTON 



growing evidence as to the fundamental mechanisms involved in the notable 

 exceptions which show acquired immunity, such as Histoplasma and Cocci- 

 dioides, the two most striking examples subjected to study by Salvin and 

 others. Progress has been made also on the subtle and previously obscure 

 conditions which, in the case of most of the deep-seated mycoses, control the 

 expression of two dimorphic types of growth, the one developing in the human 

 tissue being decidedly different from that developing in culture even on media 

 designed to simulate as closely as possible the characteristics of the tissue 

 invaded. Encouraging also has been the extension and improvement of the 

 methods of treatment of the mycoses. There has been advance in the applica- 

 tion of more effective, newly developed chemical compounds beyond the 

 standard medicaments of even a decade ago, while of the antibiotics, formerly 

 thought of chiefly in relation to diseases of bacterial origin, some have been 

 found to have notable potentialities against diseases of fungus origin as well. 



One of the most striking advances has been in the area of epidemiology, 

 where intensive investigation has yielded valuable information concerning 

 the sources and the natural reservoirs of infection of some of the more destruc- 

 tive fungus diseases of man. For example, in one of these cases, the sources 

 of the Sporotrichum responsible for severe outbreaks of sporotrichosis among 

 the native workers in the deep mines in Witwatersraand in South Africa, was 

 traced by Weintroub and associates to the timber with which the mine tunnels 

 were braced and shored, thus adding to the list of natural sources of infection 

 of this serious pathogenic fungus already known to occur as a saprophyte in 

 plant material and in the rich soil of gardens and greenhouses. In the case 

 of Coccidioides, the fungus responsible for the tuberculosis-simulating "valley 

 fever" and for the deadly systemic "coccidioidal granuloma," work pioneered 

 by Emmons has revealed that the natural reservoirs of infection are the 

 ground rodents native to the regions of the Southwest where these diseases 

 are endemic and thence carried from the soil in dust to man. More recently, 

 the work of Ajello and his associates, in the southern United States, has shown 

 the potential sources of histoplasmosis to lie in the occurrence of Histoplasma 

 in the dirt of chicken houses and chicken runs heavily enriched with fowl 

 droppings as well as in the dust from the air of such regions, while Bridges 

 and associates have shown the occurrence of this fungus in the sludge of the 

 sewage-disposal plants in Ohio. Even more recently, in the mycological pro- 

 grams of these very meetings is the report by Morrow and associates of the 

 occurrence in airborne dust in Texas of Allescheria, the fungus causing the 

 disfiguring maduromycosis. 



Corollary to the advances in our knowledge of the fungi as causes of disease 

 in man has developed an increasing body of information on the spores of 

 fungi in the air as the causative agents of the inhalant allergies included under 

 the general heading of asthma and hayfever. Active in this investigation have 

 been not only mycologists together with the sneeze, wheeze, and itch associates 



