Histoplasma Capsulatum: Its Cultivation on the Chorio-Allantoic Membrane of the Developing Chick and Resultant Lesions

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  • Barnard Free Skin and Cancer Hospital, Barnes Hospital, and Department of Dermatology, School of Medicine, Washington University, St. Louis, Missouri
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  1. 1.The chorio-allantoic membrane of the developing chick was successfully inoculated with a seven year old culture of Histoplasma capsulatum.
  2. 2.Eggs were incubated 12 days and observed 6 days after inoculation.
  3. 3.The macroscopic appearance of the lesion showed a thickened, yellowish-gray plaque with a peripheral opaque region.
  4. 4.Microscopically, there was a marked reaction in the ectoderm, mesoderm, and the underlying entoderm.
  5. 5.The cellular response consisted of the appearance of large numbers of fibroblasts, monocytes, leucocytes, red blood cells with a marked eosinophilia.
  6. 6.The organism showed a conversion into yeastlike cells analogous to the formation of arthrospores and oidia.
  7. 7.The ascus-like cells, stalagmospores or aleuriospores became converted into many yeastlike cells which seemed to indicate that they are most likely ascus-like structures, probably of a degenerate nature.