658 



STABILITY OF BACTERIAL SUSPENSIONS. in 



organisms has an isoelectric point at about pH 4.7. The small dif- 

 ference in the concentration of normal and im^mune serum required 

 to change the isoelectric point renders it improbable that this effect 

 can be ascribed to the immune body. 



Fig. 3. Effect of different concentrations of normal (upper half) and immune 

 serum (lower half) on the potential and agglutination of B. typhosus at different 

 pH 0.01 N acetate buffer. 



