Myocardial necrosis produced in animals by means of crystalline streptococcal proteinase.

Focal myocardial necrosis that was often extensive was found in a high percentage of rabbits, guinea pigs, and mice given a single intravenous injection of crystalline streptococcal proteinase. The findings are discussed in relation to their possible implications for the pathogenesis of the cardiac lesions of rheumatic fever.