518 



HEMOLYTIC SENSITIZER AND RED BLOOD CELLS 



cells is at a maximum. On the alkaline side of this point in the 

 absence of electrolyte the percentage of sensitizer uncombined 

 increases with the alkalinity and reaches a maximum of nearly 100 

 per cent at about pH 10. On the acid side of pH 5.3 the percentage 

 of sensitizer uncombined increases with the acidity but somewhat 

 less rapidly than for a corresponding increase in alkalinity. 



It is impossible to carry the observations to reactions more acid 

 than pH 4 on account of hemolysis. The fragility of heavily sensi- 

 tized cells is well known; both normal and sensitized sheep cells 



u 



100 



80 



60 



40 



20 







20 



100 



pHll 



10 



8 



Fig. 2. Curve showing the proportion of the total sensitizer present either 

 free or combined with cells, when the sensitizer dissociates from combination. 



can endure, in the absence of electrolyte, a reaction of pH 4.5 without 

 a trace of hemolysis provided they are not agitated. At this and more 

 acid reactions a considerable degree of hemolysis can be caused by 

 shaking or even gentle agitation. The agitation to which the cells 

 were subjected while in the water bath caused a trace of hemolysis 

 at all reactions; this hemolysis was apparently no greater at pH 10 

 than at pH 7.4, the normal reaction of the blood. Numerous obser- 

 vations were made on the acid side of pH 5 which are not recorded 

 because of the difficulty in satisfactory colorimetric determination 



