4 6Materials and methods. Standardized stock cultures of L-fibroblasts (mouse) obtained from Dr. Franklin Leach, Oklahoma State University, were cultured in Eagle's medium, supplemented with calf serum, a t 37.5OC. Cell suspensions for counting and/or transfer were formed by the use of a "policeman" and vigorous pipette action (201 X).Chemical #742 was supplied dissolved in by guest on July 25, 2015 ebm.sagepub.com Downloaded from