BACTERIAL AUTOLYSIS 663 



incubation. Both show a sli,u;ht decrease in biuret, antl a very 

 abrupt and pronounced decrease in amino nitrogen. This sharp 

 drop in amino nitrogen is an anomaly, and no explanation is 

 offered. 



The conductivity of the suspensions of Bad. colt remained 

 remarkably constant, except that of Via which corresponded 

 to the decrease in biuret. Of the three constant suspensions, 

 however, two were heated controls. 



The hydrogen ion concentrations of the different bacterial 

 suspensions ranged from pH 7 to pH 9. Vb was brought to 

 pH 9 bj^ the addition of sodium carbonate, while Va remained 

 of its own accord at about pH 8. Number \T had a hydrogen 

 ion concentration of pH 7. 



The results recorded here indicate that Bad. coli undergoes 

 but slight autolysis, at the best, under conditions which are 

 most favorable for this sort of enzymatic action. 



Staphylococcus aureus and Streptococcus pyogenes 



These two organisms are discussed together because they 

 showed practically the same autolytic changes, and because the 

 curves are given on the same chart (6). The results are of 

 considerable interest in that the staphylococcus, which is an 

 active gelatin liquefier, underwent but partial self digestion, 

 and the streptococcus, which possessed no gelatin-liquefying 

 property, whatever, elaborated enzymes which not only reduced 

 the biuret appreciably, but brought about a marked increase 

 in the amino nitrogen. 



Four experiments were carried out with the staphylococcus, 

 two different strains being employed. Curve 4 represents one 

 strain, and 1, 2, and 3 the other. Curves I and II represent 

 two experiments on one strain of streptococcus. All of these 

 strains showed autolytic changes, although one of the strains 

 of Staphylococcus aureus failed to give any evidence of this 

 in one of the experiments (1). The suspensions were made in 

 distilled water. 



