MEDICAL MYCOLOGY 365 



and Hopper (1939) especially helpful in diagnosis and in identi- 

 fication. 



Similarly the physician will find the Manual of Clinical Mycol- 

 ogy by Conant, Martin, Smith, Baker, and Callaway (1944) indis- 

 pensable in dealing with mycotic diseases. It discusses systemati- 

 cally and briefly symptoms, differential diagnosis, prognosis, im- 

 munology, etiology, identification, isolation and cultivation of the 

 fungus, and range of the disease. 



It would seem that medical mycology is not surpassed bv any 

 other field of mycological study in potential importance and in 

 appeal to the scientific imagination of the young investigator 

 seeking new and difficult problems whose solution means much 

 to the welfare of the human race. 



On the basis of present-day knowledge certain general state- 

 ments regarding fungi pathogenic to man appear to be war- 

 ranted. These statements are therefore categorically presented 

 in the following introductory paragraphs. In the first place the 

 number of species known to be pathogenic to man is limited. 

 These are mostly imperfect fungi; a few are Ascomycetes, closely 

 related to the yeasts, and a few are Actinomycetes, whose syste- 

 matic position is still a matter of dispute. 



Little is definitely known about their source in nature except 

 that circumstantial evidence indicates that some of them originate 

 on plants. Some species, especially among the Trichophytoneae, 

 occur also on wild and domestic animals and are transmitted to 

 man only by being implanted. 



Entrance to the body is gained (a) through hair follicles, but 

 never through sweat glands, (b) through the nasal passages and 

 thence into the lungs, and (c) through abrasions or injuries, as 

 through scratches or wounds made by thorns or splinters. In a 

 few species entrance appears to be gained through the enteron. 



The types of tissue reactions induced in man by fungi are ex- 

 tremely variable. Some species remain quite superficial in their 

 effect, whereas others produce deep lesions or involve such internal 

 organs as the lungs, spleen, and liver. Some are local, and some 

 systemic. Among the common tissue changes are congestion, 

 edema, exudation, hyperplasia, necrosis, scar-tissue formation, and 

 suppuration with accompanying migration of polymorphonuclear 

 cells. 



