348 CLINICAL BACTERIOLOGY. 



culous subjects. Experimental transmission of the dis- 

 ease has succeeded in several instances, but the culture of 

 the fungus has not. 



Erythrasma, a circumscribed erythema of the skin, is 

 caused by the microsporon minutissimum, the small, round 

 spores of which lie in the superficial horny cells, whereas 

 the mycelium, consisting of small, delicate, convoluted 

 and branched filaments, in part interlacing and with short 

 segments, extends more deeply. 



Psoriasis is no longer included by dermatologists among 

 the parasitic diseases, its supposed excitant, the epidermo- 

 phyton, having been recognized as a factitious product 

 (Ries). 



PHARYNGOMYCOSES. 



In the pharynx mycoses are not at all rarely observed in 

 certain situations. The fungous vegetations appear as 

 small, porcelain-white plugs, mostly in the lacunae of the 

 tonsils. They consist, however, as a rule, not of true 

 molds, but more commonly of filaments of the leptothrix buc- 

 calis (mycosis pharyngis leptotliricid), whose botanic position 

 has not yet been clearly made out, but which is ordinarily 

 included among pleomorphic bacteria. Miller differentiates 

 a leptothrix buccalis innominata, maxima, and gigantea. 

 The leptothrix is a constant inhabitant of the oral cavity ; 

 and its fine threads, from 0.5 to 0.8 p. thick, are frequently 

 found on examination of the sputum. The straight, wavy, 

 or spiral threads of the leptothrix are made up of rod-like 

 or spiral segments. In the filaments a base and an apex 

 may often be distinguished ; at their free extremities spher- 

 ical formations appear, which in part have been considered 

 arthrospores. The appearance of this fungus is thus quite 

 similar to that of the simple varieties of molds. Accord- 

 ing to some observers, these detached "spores" may, like 

 true cocci, divide in pairs. In that event the fungus would 

 belong to the bacteria, and would be included among the 

 pleomorphic varieties. The leptothrix stains yellow with 

 solution of iodin and potassium iodid. 



Abundant opportunity is afforded for the entrance of the 

 fungus into the lacunae of the tonsils, as the inhaled air and 

 articles of food always contain fungi. In the secretion of 

 the oral cavity leptothrix and filamentous fungi are always 

 present normally. The vegetation of the fungus in the 



