602 



THE STREPTOCOCCI OF MAN 



[The chemical characters, pathogenic properties, etc. of each of the groups 

 are shown in the subjoined table which has been compiled from Andre wes 

 and Horder's papers in the Lancet, 1906 ii. 



[It is not pretended by the authors that this is a hard and fast classification, 

 on the contrary, it is frankly admitted that one group fades insensibly into 

 another : " we venture to believe that some such conception of the streptococci 

 as we have set forth is preferable to the idea that they are all one kind or that 

 they present a hopeless chaos " (Andrewes and Horder). 



3. Toxins. 



1. Roger grew a streptococcus anaerobically in meat broth at 30 C. for 5 

 days and then filtered the culture through porcelain. 



When inoculated into the veins of a rabbit in doses of 15-20 c.c. per kg. of body 

 weight the filtrate caused diarrhoea and wasting and the animal died in 2 days. 

 Rabbits inoculated with 5-12 c.c. of the filtrate and subsequently (15-30 days later) 

 with a virulent culture died more quickly than control animals. On the other hand, 

 if the filtrate were heated to 104 C. and then inoculated into the veins in doses 

 of 5-30 c.c. it produced a certain degree of immunity. From this it must be assumed 

 that the filtrate contained two substances, one, thermolabile at 104 C. and precipitable 

 by alcohol, which was toxic and predisposed to infection, the other, thermostable at 

 104 C. and possessing immunizing properties. 



1 Mostly terminal or chronic infections. 



2 Principally from cases of scarlet fever. 



