PAUL H. De KRUIF 



389 



original culture. The centrifugation and resuspension in distilled 

 water were repeated four times in all. The final suspensions were 

 carefully brought to a uniform turbidity. 



EXPERIMENTAL. 



All experiments were carried out by adding 1 cc. of distilled water 

 suspension of the microbe in question to an equal volume of each of 

 the buffer mixtures just described. The tubes were carefully shaken, 

 placed in the water bath at 43°C. and readings taken at 1, 2, and 16 

 hours. 



TABLE III. 



Acid Agglutination Optimun of Microbes D and G, Strain R 15. 

 Na Lactate-Lactic Acid Buffer Series. 



In this and the following tables lesser degrees of floculation are recorded as 

 + + ■+, and Tr. (trace). C indicates complete flocculation. 



The agglutination optimum was considered to be that zone of 

 Ch"*" where complete flocculation occurred; that is, where the microbes 

 sedimented so perfectly as to leave a water-clear supernatant fluid. 

 Lesser degrees of agglutination are recorded as ++, +, and Tr. 

 (trace). The readings are greatly facilitated by holding the tubes 

 before a powerful beam of light, projected downward in front of a 

 dark background. 



Experiment 1. Acid Agglutination Optimum, Microbes D and G, Strain R 15, 

 in Na Lactate-Lactic Acid Bujjer Series. — Suspensions of Microbes D and G, 

 isolated from Strain R 15, bacillus of rabbit septicemia, were tested against the 

 Na lactate-lactic acid buffer scries. The experiments were carried out as de- 

 scribed above. The results are recorded in Table III. 



