1. From the Pathology Division, Bureau of Laboratories, Center for Disease Control, Public Health Service, Department of Health, Education, and Welfare, Bldg. 1/Room 2301, Atlanta, GA 30333, where reprint requests should be addressed to Center for Disease Control, attention of Dr. Chandler. (Requests for the Center's modification of the Dieterle silver-impregnation staining method should be similarly addressed.)