Experimental maduromycosis in the laboratory mouse

Summary 1. A 0.5 ml inoculum containing 1.4×10⁴ spores and/or mycelial fragments ofAllescheria boydii when injected intraperitoneally, did not cause death in 18–20 g female Swiss mice in 18 days.2. Focal, pin-point lesions developed in the liver and spleen of mice injected with the stock suspension and the 1:10 dilution of it (2.8×10⁴ and 2.8×10³ infective units ofA. boydii per ml, respectively); no lesions developed from the 1:100 dilution of the original suspension.3.Allescheria boydii was recovered from the livers and spleens of all mice, as well as from the peritoneal exudate of one mouse injected with the stock suspension ofA. boydii; the fungus was not isolated from heart's blood.4. Inability to cause death by the intraperitoneal injection ofA. boydii inocula might be attributed to the natural defense mechanisms in the mice or to the excessive dilution of the inoculum; it is improbable that any genetically controlled resistance to allescheriosis exists in the mice used in this study.Paper no. 664, Department of Botany and Plant Pathology, Ohio State University, 1735 Neil Avenue, Columbus 10, Ohio.This is the report of research done by the junior authors with the guidance of the senior author during a course in medical mycology in this department.