A notable attempt has been made by Crowe to simplify the classification of chronic arthritis on a pathologic and etiologic basis. His discussion of foci of infection opens the way to much further research, though it is quite possible that the teeth have been overemphasized in this regard as contrasted with other organs. Crowe's two most important contributions are on the bacteriology of ostearthritis, which he believes to be due to streptococci, and of rheumatoid arthritis, for which he claims staphylococci as the etiologic factor. The evidence is not convincing for either claim. His attempts at classification and differentiation of the streptococci and staphylococci are noteworthy, but one would feel more favorably inclined were the differentiation in the former based to a greater extent on factors other than Crowe's medium. And bacteria which so constantly change in their biologic reactions must be viewed with considerable skepticism as forming distinct varieties.