Lesions 387 



sterile pipet, and cultivated it upon artificial media, acid 

 vegetable infusions seeming best adapted to its growth. 

 It develops scantily at the room temperature, better at 

 37 C. in from four to five days. In twenty to thirty 

 days a colony attains the size of a little pea. 



Bouillon. In bouillon and other liquid media the 

 organisms form little clumps resembling those of actino- 

 myces. They cling to the glass, thus remain near the 

 surface of the medium, and develop a rose- or bright-red 

 color. Those which sink to the bottom form spheric balls 

 devoid of the color. 



Gelatin. The growth in gelatin is not very abundant, 

 and forms dense, slightly reddish, rounded clumps. Some- 

 times there is no color. There is no liquefaction. 



Agar-agar. Upon the surface of agar-agar beautiful 

 rounded, glazed colonies are formed. They are at first 

 colorless, but later become rose-colored or bright red. 

 The majority of the clusters remain isolated, some of them 

 attaining the size of a small pea. They are usually 

 umbilicated like a variola pustule, and present a curious 

 appearance when the central part is pale and the periphery 

 red. As the colony ages the red color is lost and the colony 

 becomes dull white or downy from the formation of aerial 

 hyphae. The colonies are very adherent to the surface of the 

 medium, and are almost of cartilaginous consistence. 



Milk. The organism grows in milk without causing 

 coagulation. 



Potato. Upon potato the growth of the organism is 

 meager and slow, with very little chromogenesis. The 

 color-production is 'more marked if the potato be acid in 

 reaction. Some of the colonies upon agar-agar and potato 

 have a powdery surface, either from the formation of spores 

 or of aerial hyphse. 



Lesions. Microscopic study of the diseased tissues in 

 mycetoma is not without interest. The healthy tissue is 

 sharply separated from the diseased areas, which appear 

 like large degenerated tubercles, except that they are ex- 

 tremely vascular. The mycelial or filamentous mass 

 occupies the center of an area of degeneration, where it 

 can be beautifully demonstrated by the use of appropriate 

 stains, Gram's and Weigert's methods being excellent for 

 the purpose. The tissue surrounding the nodes is infiltrated 

 with small round cells. The youngest nodules consist of 



