During the winter of 1957 and 1958, considerable loss was reported in prime and choice beef carcasses as the result of hemorrhage in the muscles of the chuck. The meat packers were concerned about this loss since approximately four percent of the heavy beef in some plants were showing these lesions. The incidence of the muscle lesions was highest in beef killed according to ,the Kosher ritual, and since this represents select beef, the loss was of considerable importance because the involved chucks were unsalable or were sold at a reduced price.