1. From the Laboratory of Virology, New York Blood Center, the Department of Pathology, New York Hospital-Cornell Medical Center, the Plasma Proteins Laboratory, the New York Blood Center and Department of Biochemistry, Cornell University Medical College, and the Biologic Laboratories, State Laboratory Institute, Massachusetts Department of Public Health, Boston, Mass, (address reprint requests to Dr. A. M. Prince at the New York Blood Center, 310 E. 67th St., New York, N.Y. 10021).