Although acute muscular rheumatism is generally conceded to be an infectious process, the myalgias and milder forms of myositis are not so definitely accepted as such. Myalgic pains are considered by Taylor1 to be the result of faulty metabolism, by Gordon2 of excessive katabolism from over-exertion of muscle cells, and by Profanter3 as the peripheral expression of pain caused by defective function or injury of visceral organs. Except among English writers, such as Poynton,4 Llewellyn and Jones,5 Munroe and Almond,6 and Stockman and Renton,7 little credence is given to the idea of localized invasion of the muscles by bacteria other than in marked acute generalized myositis, and the condition described as dermatomyositis. The demonstration by one of us (Rosenow8) eight years ago that streptococci from patients with rheumatic fever with muscular involvement, and streptococci from patients with acute nonrheumatic myositis,9 tended to localize and produce nonsuppurative lesions in muscles of