Abstract
Chick myogenic cells grew in the presence of a small amount of avian serum in a culture medium composed of Eagle''s minimum essential medium (MEM) and horse serum. Mammalian sera, except for fetal bovine serum at high concentrations, could not substitute for the avian serum. Rat myogenic cells grew in the presence of a small amount of mammalian serum in a culture medium composed of MEM and chick serum. Avian sera, except for dove serum at high concentrations, could not substitute for the mammalian serum. Serum from animals of the class from which the myoblasts were obtained was needed for cell growth. There is a class specificity among sera in regard to myogenic cell growth. The only exceptions presently found were fetal bovine and dove sera.