BACTERIAL AUTOLYSIS 675 



As SO few tests were made with the Staphj'lococcus and Strep- 

 tococcus no further comment should be necessary than to state 

 in review that both of these organisms showed distinct evidence 

 of elaborating; enzymes which have appreciable autolytic action, 

 especially the staphj-lococcus. 



The results obtained with the pneumococcus, gonococcus and 

 meningococcus indicate that these organisms undergo autolytic 

 changes as the result of their own enzyme action, and particularlj' 

 the meningococcus and the gonococcus. This is further sub- 

 stantiated in the case of the two last mentioned organisms by the 

 microscopic examination of stained slides in which decreased 

 staining ability and change in cell morphology are shown during 

 the course of the autolysis, as had been observed previously by 

 Flexner (1907) for the meningococcus. 



StTMMARY AND CONCLUSIONS 



It has been possible to follow in a quantitative way the nitrog- 

 enous changes taking place in autolyzing bacterial suspensions. 

 In this studjr the quantitative biuret test of Vernon and the 

 Sorensen titration have proven of the greatest value. The 

 Van Slyke determination of amino nitrogen has also been em- 

 ployed to advantage, although the material to be analyzed was 

 not particularly suited to this method. Electrical conductivity 

 has been found to increase during autolysis, but its increase has 

 not been proportional to the amount of amino nitrogen formed 

 by the hydrolysis of protein, as Bay liss (1907-8) claims to have 

 found to be the case in the tryptic digestion of caseinogen and 

 gelatin. 



By the application of such methods it has been possible to 

 show that: 



1. Proteolytic bacteria of the type of Erythrobacillis prodig- 

 iosus, Pseudomonas pyocyanea, and B. subtilis autolyze rapidly. 



2. Bad. coli undergoes slight changes which may be autolj'- 

 tic in nature, but which at best involve only a small part of the 

 complex nitrogenous constituent or constituents of the cells. 



3. The pathogenic cocci, pneumococcus, gonococcus and men- 

 ingococcus undergo an actual autolysis with a breaking down of 

 the protein or protein-like substances of the bacterial cells. 



