550 



PATHOGENIC FUNGI 



of the organism and led to its being denominated oidwm 

 coccidioides. 



The organisms isolated from these varying lesions are 

 evidently all closely allied, although probably not identical. 

 In blastomycetic dermatitis the organisms are present chiefly 

 in the abscesses in the corium and to a less extent in the more 

 superficial suppurations, and can be demonstrated by mounting 

 the pus -in 30 per cent, caustic potash solution. They are 

 spherical Jin form, 8 to 10 ft. in diameter, and appear singly, in 

 pairs, orjless frequently in larger groups (Fig. 173). There is 

 a central protoplasm without a nucleus, separated by a delicate 



membrane from a sur- 

 rounding clear space, 

 and the whole is en- 

 closed in a highly re- 

 tractile, double - con- 

 toured capsule. Bud- 

 ding is frequently seen. 

 The organisms stain with 

 hasmatoxylin and with 

 aniline dyes and are 

 Gram-positive, the re- 

 action of the capsule 

 being variable. The 

 organisms present in the 

 generalised infections 

 are much more numer- 

 ous in the tissues and 

 attain the size of 35 fi. 

 In these also there are 

 appearances in the protoplasm which suggest endogenous 

 sporulation. The facility with which the fungi have been 

 cultivated varies in different cases, but growth can usually 

 be readily obtained at room temperature or at 37° C. on 

 ordinary media, but preferably on Sabouraud's maltose medium, 

 especially when this is made slightly acid. Growth appears 

 in from two to seven days, and the characteristics vary. 

 In some cases moist, paste-like colonies develop, in others 

 the surface appears crumpled, and sometimes it is dry and 

 powdery. These differences are associated with differences 

 in the degree of mycelial formation, in the extent of the 

 ingrowth of the organism into the medium, and in the 

 presence or absence of aerial conidia. The effects of the 

 different varieties differ. Glucose and maltose are usually 



Fig. 174. — Miorosporon furfur ; scraping from 

 skin. Stained by Gram, x 1000. 



