Biochemical and Immunological Properties of Histoplasma Capsulatum No. 650 *

The morphological identification of the causative agent of "histoplasmosis" made possible the recognition of the disease and disclosed its wide distribution.t However, it is only by a more complete understanding of the biochemistry and immunology of this organism that its pathological action may be explained. Only scattered dbservations have *been reported3 6, 8, 9, 15 and the present investigation was to provide further information along these lines. In planning the work it seemed wise to restrict the study to a single strain and for this purpose strain No. 650 of Histoplasma capsulatum was used. This strain originated from a case reported by Rhodes and his associates10 in 1941; it conformed in every respect to the mycological criteria required of this organism.