494 WILBXJRT C. DAVISON 



the saline in which the washed organisms had been suspended 

 and then allowed to disintegrate, were both bacteriolytic. 



The growth from several "moth eaten" colonies of the thirty- 

 fourth generation of the "sensitive" strain described above was 

 inoculated into 100 cc. of peptone water. This culture was 

 incubated ninety-six hours at 37°C. and then filtered. This 

 filtrate was as strongly bacteriolytic as that of the eighth genera- 

 tion. This bears out Bordet's and Ciuca's (Davison, 1922) 

 statement that "sensitive" strains are lysogenic for numerous 

 generations. 



FILTRATES OF AGAR CULTURES OP A 



STRAIN OF BACT. DYSENTERIAE (fLEXNEr) 



The twenty-four hours' growth of "moth eaten" colonies on 

 five agar plates of the fifth generation of the "sensitive" strain 

 of Flexner bacilH described above was suspended in 20 cc. of 

 N/10 phosphate solution at pH 8" and centrifuged. The super- 

 natant phosphate solution was then filtered. This filtrate was 

 strongly bacteriolytic (table 11). The sediment of organisms, 

 which was a mass of mucoid, stringy material, was resuspended in 

 20 cc. of N/10 phosphate solution and ground up in a rotary 

 agate mortar.' This suspension was then filtered. This filtrate 

 was also strongly bacteriolytic (table 11). In other words the 

 phosphate solution in which the sensitive organisms were washed 

 and also the solution which contained the products of the ground 

 up organisms were both bacteriolytic, suggpsting that the lytic 

 principle was extracellular as well as intracellular. 



The twenty-four hours' growth of regular colonies on nine 

 agar plates of a normal strain of Flexner bacilU was suspended in 

 20 cc. of N/10 phosphate solution at pH 8 and ground up in a 

 rotary agate mortar. This suspension was then filtered. This 

 filtrate had no bacteriolytic activity (table 11). 



= N/10 Na^HPO,, 1.95 parts, and N/10 KHsPO,, 0.05 part. This solution 

 itself was not bacteriolytic. 



' The grinding was done by Dr. L. B. Lange of the Johns Hopkins School of 

 Hygiene, to whom my thanks are due. 



