CALVIN B. COULTER 



315 



solution of the usual strength. The titrations for H concentrations 

 of the sensitized cells were carried out according to the method already 

 described. 



The determinations for normal and sensitized cells have been 

 recorded in the form of curves (Figs. 2 and 3) in which the millimeters 

 of movement during 10 minutes time are plotted as ordinates against 

 the pH values as abscissae. From these curves it appears that the 



•d 



> 



o 



e 





65 6.0 5.5 5.0 4.5 4.0 3.5 pH 



Fig, 2. Curve showing the movement in mm. during 10 minutes of normal 

 red blood cells at varying hydrogen ion concentrations. The points above the 

 curve between pH 4.0 and 5.0 represent determinations on different specimens 

 of blood from those recorded in the points below the curve, so that the difference 

 may represent actual variations in individual specimens. 



direction and rate of movement in the electric field of both normal 

 and sensitized red blood cells is a function of the hydrogen ion concen- 

 tration. At concentrations less than pH 4.6 the charge carried is 

 negative and increases in amount with the alkalinity; pH 4.6 repre- 

 sents the isoelectric point; at concentrations greater than pH 4.6 the 

 charge carried is positive and increases in amount with the acidity. 



A comparison of the two curves shows that on the alkaline side of 

 the isoelectric point the charge of normal cells is greater and increases 



