STREPT. ERYSIPELATIS AND STREPT. LACTICUS. 183 



From these results the following deductions may be made : — 



A difference in the degree and also the rate of proteolj^sis between 

 Streptococcus erysipelatis and Streptococcus lacticus is shown. 



Again, it seems to suggest a correlation between the proteolysis, also, 

 and the precedmg environmental factors as stated under "Rate of Growth." 

 Streptococcus erysipelatis existing in the animal body rich in body proteins 

 with only a slight amount of carbohydrate present and at 37° C, with 

 Streptococcus lacticus existing in a medium of abundant carbohydrates 

 as well as protein substances and at 20° C. or less, must be influenced by 

 their former habitats. 



According to this stimulation, generally recognized by physiologists, 

 Streptococcus erysipelatis would naturally give rise to abundant proteo- 

 lytic enzymes, while Streptococcus lacticus would produce enzymes acting 

 on carbohydrate dactose). Such a case seems to be indicated in the 

 present work. 



Determination of Hydrogen Ion Concentration as Growth pro- 

 gressed. ^ 



Table 4. — Pji in Media. 



Set 1 — Streptococcus erysipelatis. 

 Set 2 — Streptococcus lacticus. 



Table 5 indicates the occurrence of an adjustment (automatic adjust- 

 ment) ^ of the hydrogen ion concentration in the media. Attention was 

 called to this phenomenon and its probable explanation given in the 

 previous work. ' 



> This has been explained previou.sly. 



2 See p. 172. 



3 See p; 174. 



