MORPHOLOGY IN CULTURE 



191 



coses and its usefulness as a diagnostic 

 test remains to be proved. An antigen 

 has also been prepared from glucose 

 broth.«- ^-' " 



Prognosis and Treatment. With very- 

 few exceptions, recognized cases of histo- 

 plasmosis have terminated in death. 

 There is some evidence indicating that 

 the disease occurs in a mild and unrecog- 

 nized form. Some apparently healthy 

 individuals react strongly to intradermal 

 injections of histoplasmin, and lesions 

 have been found by accident in individuals 

 apparently dying of other causes. How- 

 ever, treatment of diagnosed cases has 

 been ineffective. IMeleney " recommends 

 the use of the organic salts, the trivalent 

 organic preparations, and the pentavalent 

 preparations of antimony. 



Morphology in Tissue. In tissue the 

 fungus is a small oval budding cell meas- 

 uring about 3 by 5 microns including the 

 capsule. It appears principally within 

 cells of the reticuloendothelial system. 

 Extracellular fungi are also numerous 

 when infection is heavy. The stainable 

 protoplasm of the fungus cell in most 

 pathological preparations is in a cup- 

 shaped mass at one end of the cell. This 

 no doubt represents shrinkage in part and 

 the presence of a normal cell vacuole in 

 part. The minute nucleus is not apparent. 

 Each cell may be surrounded by a narrow 

 capsule. 



Morphology in Culture. "When Histo- 

 plasma capsulatum is grown in culture on 

 blood agar at 37° C. it produces budding 

 cells like those seen in tissues.^- * Under 

 these conditions of culture newly isolated 

 strains may grow exclusively in the bud- 

 ding form. However, many old strains and all strains when grown on 

 American Sabouraud agar or other common media at 30° C. or at 



Fig. 97. Histoplasma cap- 

 sulatum. Young and old 

 cultures on modified Sa- 

 bouraud agar medium. 



