This investigation was supported by research grants 1409 and B-398 from the National Institute of Neurological Diseases and Blindness, of the National Institutes of Health, Public Health Service. Technical assistance was given by Drs. Jane C. Kaltenbach, Stephanie H. Barch, and Yu-Ying Fu.
Virginia M. McMurray
Department of Zoology, State University of Iowa, Iowa City, Iowa
Rockefeller Institute for Medical Research, New York City