162 BACTERIOLOGY FOR NURSES 



duced when inoculated into rabbits characteristic arthritic lesions. 

 The question as to the specificity of the streptococcus found in 

 rheumatism is as yet unsettled. In certain cases of chronic 

 arthritis hemolytic streptococci have been isolated from the 

 tonsils which when injected into certain animals have invariably 

 produced arthritis. Removal of the tonsils in such cases generally 

 results in marked improvement or recovery. 



Several epidemics of sore throat due to streptococci have arisen 

 from time to time, many of which have been traced directly to 

 the milk supply. It is thought that such streptococci come 

 originally from a septic human throat, find their way into the 

 milk ducts, probably from the hands of a milker, and multiply 

 there without causing any perceptible inflammatory condition 

 in the eow. The bovine type of streptococci which produce 

 inflammations of the udder of the cow has different cultural 

 characteristics and is apparently not identical with those found 

 in human septic sore throat. 



As already stated, a satisfactory classification of streptococci 

 from different sources is extremely difficult. Association with a 

 specific pathologic, condition is not conclusive that the organism 

 is the causal agent of that and of no other condition. A strain 

 isolated from suppurative processes may produce erysipelas, and 

 conversely abscess formation may be produced by one isolated 

 from erysipelatous lesions. Classification according to aggluti- 

 nating reactions or the ability to ferment different sugars have 

 likewise given insufficient aid in determining whether the strepto- 

 cocci are one or several species. 



Immunity. Streptococcus inflammations apparently do not 

 stimulate the human body cells to produce immunizing anti- 

 bodies. It is true that some protective substances must be pro- 

 duced or recovery would not take place. Evidently, however, they 

 soon disappear, leaving the individual as susceptible as before. 



An interesting experiment was tried by Koch and Petruschky 

 on a man suffering from a malignant growth. They inoculated 

 him subcutaneously with streptococci obtained from a case of 

 erysipelas and produced in him a moderately severe attack of 



