Cc. X-ray diffraction and electron microscope studies on silver salmon spermatozoa In the X-ray diffraction studies of silver salmon spermatozoan tails, orientation of tails in a parallel configuration was done by (1) quick-freezing a flowing suspension of tails both on glass plates and in capillaries and (2) by orientation in an electric field. In X-ray diffraction work with undried tail preparations, the use of antibiotics (penicillin G, streptomycin sulfate) resulted in marked agglutination effects, thus the steps for preparing pure suspensions of tails could not be accomplished. The use of benzene and toluene as antibiotics gave similar results. Osmic tetroxide at a concentration of .05 per cent has been tried with some success. Sufficient purified tail fibril material has not been obtained for extraction of actomyosin. As a test for survival in cold storage, were mixed with 10 per cent glycerol, then cooled rapidly to ~79°C. the spermatozoa cooled slowly to -5°C, The spermatozoa were found to be motile after thawing. During the summer of 1953, electron microscope studies on silver salmon spermatozoa were made. An ultramicrotome and an improved RCA-EMU-type electron microscope provided by