EN
Five vervet monkeys (Cercopithecus aethiops) and two baboons (Papio doguera) were experimentally infected with Trichinella spirails. The animals were killed two to three months later and larval densities were determined in twelve muscles from each animal. The lowest mean larval densities were found in the diaphragm which averaged 1,807 per g. as compared with more than 3,000 per g. for the biceps, masseter, tiblalis anticus and flexor carpi ulnaris. Although there is a widespread belief that the diaphragm is the most heavily infected muscle in man, this is not confirmed from the limited number of necrepsies reported in the lierature. Further information on the larval densities in the different muscles of man is necessary as a guide to the best sites for biopsy, and to facilitate prevalence surveys based on the examination of material obtained postmortem.