BACTERIAL AUTOLYSIS 



559 



complete evidence as possible concerninp; so-called "autolysis" 

 in certain organisms selected for tlie purpose. As the work 

 concerned entirely changes going on in the complex nitrogenous 

 substances of the dead bacterial cells, the following methods 

 were employed and found in a large measure to supplement 

 one another and to act as checks on each other: 



1. The quantitative biuret test as used and advocated by Vernon. 



2. The Sorensen method for the determination of amino nitrogen. 



3. The Van Slykc method for the determination of amino nitrogen. 



4. The conductivity test. 



5. Staining and microscopic examination of the bacterial cells. 



8. suBriLia 



B. COL/ 



^ B ProCTANLUS 

 @ S RAMOSUS 



lO /S ■ ^O 2S 



Title m OATS 



Chart 1. B. subtilis, B. mycoides, Bact. coli, and Ps. pyocyanea 



The biuret readings are expressed in percentage of Witte's peptone which will 

 give a color of equal intensity. 



The Sorensen figures are expressed in the number of cubic centimeters of ^ 

 NaOH required to neutralize the amino acids in 100 cc. of the solution. 



Erythrobacillus prodigiosus 



This organism was chosen because it readily undergoes autol- 

 ysis and can be easily obtained in large quantities. The ac- 

 companying charts (charts 2 and 3) show the course of changes 



