402 



Dr. E. W. A. Walker. 



[May 16, 



every week. Cultures were also established in bouillon, gelatin, and milk. 

 These were all incubated at 37° C, and were sub-cultivated every three 

 days — the bouillon culture into fresh bouillon, the gelatin culture into gelatin, 

 and the milk culture to milk. 



After the lapse of a month, and again after two months, the streptococci 

 growing in bouillon, gelatin, and milk respectively were examined as 

 regards their reactions in the test media. In the meantime the organism 

 from the original stock was being passed through a succession of mice. It 

 was recovered in each case post mortem from the blood of the mouse, plated 

 for purity, tested in Gordon's media, and again inoculated into a fresh 

 mouse. In this manner five successive passages were carried out, and the 

 reactions of the streptococcus recorded after each passage. 



Results. 



In Table I are shown the reactions of the streptococcus A as originally 

 isolated, and after its continued cultivation in bouillon, gelatin, and milk at 

 37° C. for periods of one month and two months respectively. It is seen 

 that in every case the original reactions underwent important changes. 

 Fifteen changes of individual reactions occurred in total, and four new sets 

 of reactions made their appearance in the course of the experiment in 

 question. The power of clotting milk was lost in every case, and only 

 the neutral red, saccharose, and lactose reactions remained entirely 

 unchanged. Thus, so far as the fermentation tests afford information, 

 streptococcus A and its derivatives in bouillon, gelatin, and milk present 

 five distinct varieties or strains of streptococcus. 



Table I. — Showing the Eeactions of Streptococcus A when first Isolated and 

 after Cultivation in different Media. 



Streptococcus A. 



Milk. 



Neutral red. j 



Saccharose. 



Lactose. 



1 



■A 







Mannite. 



Changes after 

 one month. 



Changes after 

 the second 

 month. 



Aoid. 



Clot. 



When originally isolated 



+ 



+ 







+ 





+ 



+ 

















+ 











+ 





+ 



+ 



+ 







2 







+ 











+ 



+ 











+ 



+ 





3 



After 1 month in gelatine 



+ 











+ 



+ 



+ 







+ 







2 







+ 













+ 





+ 



+ 









1 

















+ 



+ 





+ 







+ 



3 







+ 











+ 













+ 







4 



