THE SPORES OF HISTOPLASMA

Abstract

Tuberculate spores distinguish the mold stage of Histoplasma from that of related pathogenic fungi. The tuberculations are not thickenings of the spore wall. They are extensions of the spore contents through the wall openings. The whole or the tip of a tuberculation may become detached and act as a spore. The yeastlike pathogenic phase of Histoplasma originates either from the hyphae, from the small spores (conidia), or from the tuberculations of the large spores (chlamydospores). Histoplasma can be recovered in culture from the lungs of white mice that have inhaled the spores. No chlamydospores have been discovered in sections of their lungs. Nevertheless, in districts of high histoplasmin sensitivity, when lungs with nodules are examined in routine autopsies, the finding of any spherical body with external spores might well suggest an arrested histoplasmosis.