AN OUTBREAK of an unusual form of pulmonary disease occurred at Camp Gruber, Okla., in March, 1944.* The illness affected 27 men and was characterized by sudden onset and severe and prolonged clinical course with slow recovery. Most patients showed diffuse infiltration of the lungs. The etiology of the disease was not known. All the men involved had spent some time 10 days previously in a storm cellar on the military reservation.
In 1952, Histoplasma capsulatum was isolated from the soil in the storm cellar.3 In 1951 and 1952, skin tests were performed on 22 of the men who were involved in the pneumonitis outbreak; all reacted to histoplasmin, whereas only 6 reacted to tuberculin, 3 to blastomycin, and 1 to coccidioidin.3 Disseminated pulmonary calcification was observed by x-ray examination in 16 of 22 men who had pneumonitis at Camp Gruber. On the contrary, such calcifications could not