SCARLET FEVER. 263 



nutrient agar-agar, nutrient gelatine, and in broth, both at the 

 ordinary and at higher temperatures, and also by experiments on 

 animals. They concluded that it could be stated with certainty 

 that the organisms in question did not stand in causal relation to 

 scarlet fever. They considered that special methods of microscopical 

 and biological research were apparently needed for demonstrating 

 the true scarlet fever contagium, which probably was especially 

 present in the skin. They considered that the presence of the 



a. b. c. 



FlG. 125. PURE-CULTIVATIONS OF STREPTOCOCCUS PYOGENES. 



(a) On the surface of nutrient gelatine ; (b) In the depth of nutrient gelatine : 

 (c) On the surface of nutrient agar. 



streptococcus was due to a secondary infection, to which the door 

 was opened by the lesions of the throat a view which was sup- 

 ported by the fact that the organisms were found in submaxillary 

 lymphatic glands. They preferred to use the term " secondary " 

 to " complicated " or " combined " infection, because this expresses 

 the fact that by the effect of the scarlatinal virus the soil is 

 rendered suitable for this ubiquitous microbe when it has once 

 gained an entrance. 



This streptococcus was found by Klein in five out of eleven cases 



