SCARLET FEVER. 527 



rose above normal. The indices for Stapliy- 

 lococcus aureus, pneumococcus and a strain of 

 Streptococcus viridans from a normal throat 

 did not show a variation from the normal. 

 Agglutinins common to M. rlieumaticus and strep- 

 tococci were found to follow the same course as 

 the opsonic index. Immunization of rabbits with 

 M. rlieumaticus resulted in the formation of opso- 

 nins for both this organism and Streptococcus 

 pyogenes. These findings would indicate that 

 streptococci play an essential part in acute articu- 

 lar rheumatism. The fact remains, however, that 

 streptococci cannot always be cultivated from the 

 lesions of rheumatic fever ; hence it is possible that 

 the organism may exist as a mixed infection with 

 more or less constancy, and that the real cause is 

 as yet unknown (Phillip). 



The theory that scarlet fever is of streptococcus Relation of 

 etiology has been held particularly by Babes, ? r fca?i C et cc 

 Klein, Moser, Gordon and Baginsky and Sommer- Fever - 

 feld. Some have held that streptococci isolated 

 from the disease show distinctive properties and 

 deserve the name of Streptococcus scarlatina. This, 

 however, is not agreed to by most bacteriologists, 

 the organisms not differing from streptococci ob- 

 tained from various sources. The organisms are 

 not found constantly in the erythematous eruption. 



Virulent streptococci are found on the tonsils 

 almost invariably in scarlet fever. In 65 per cent, 

 of the cases a membrane is formed (Ranke), and 

 this is often due to the streptococcus, which is 

 sometimes, however, associated with diphtheric 

 infection. The frequency with which streptococci 

 invade the blood during scarlet fever is related to 

 the severity of the disease. Occasionally they are 



