The Melanoid Form 443 



granulation -tissue, whose development is checked by early 

 coagulation -necrosis. Giant-cells are few. 



Not infrequently small hemorrhages occur from the 

 ulcers and sinuses of the diseased tissues; the hemorrhages 

 can be explained by the abundance of small blood-vessels 

 in the diseased tissue. 



The Melanoid Form of mycetoma has been carefully 

 investigated by Wright * and appears to depend upon an 

 entirely different micro-organism properly classed among the 

 hyphomycetes. It is probably identical with the organism 

 described by Boyce and Surveyor. 



In the case studied, Wright found the diseased tissues, 

 consisting of several of the pads of the toes, to be either 

 translucent and myxomatous or yellowish and necrotic in 

 appearance. The black granules were embedded in the 

 tissue and appeared mulberry- like and less than i mm. in 

 diameter. They were firm, and when enucleated and 

 pressed between cover and slide did not crush. Only after 

 digestion with a solution of caustic potash and careful 

 teasing could the granules be resolved into the hyphae of 

 the mold. The central part of the granule formed a reticu- 

 lum, with radiating, somewhat clavate elements projecting 

 from it. 



In sections of tissue it was found possible to stain the 

 fungus with Gram's and Weigert's stains, though prolonged 

 washing removed most of the dye. 



Cultural Characteristics. Enucleated granules carefully 

 washed in sterile bouillon and then planted upon agar-agar 

 afforded cultures of the mold in 25 out of 65 attempts. 



The growth began in five or six days, appearing on solid 

 media as a tuft of delicate whitish filaments, springing from 

 the black grain, and in a few days covering the entire surface 

 of the medium with a whitish or pale brown felt-work. 

 Upon potato this felt-work supports drops of brownish 

 fluid. The long branched hyphae thus formed were from 

 3 to 8 fi. in diameter, with transverse septa in the younger 

 ones. The older hyphae were swollen at the ends. No buds 

 were observed. No fruit organs were detected. In fluid 

 media the filaments radiated from the central grain with the 

 formation of a kind of puff-ball. Eventually the whole 



* "Journal of Experimental Medicine," vol. in, 1898, p. 421. 



