576 



PHAGOCYTOSIS OF SOLID PARTICLES. Ill 



study of the comparative rates of phagocytosis of carbon and quartz 

 particles to determine whether or not carbon is ingested by leucocytes 

 more readily than would be predicted from the calculated chances 

 of collision. 



The method of calculating R, the chance of collision, and the experi- 

 mental procedure are described in the earlier papers (4, 5). It must 



lo^A-x 



QucirTz 4.08/1 

 X = Carbon 4.7/1 



LogA-x 



oe = Quartz 4.08a 

 X - Carbon 4.7>u- 



3 Hours 



1 



Z flours 



Fig. 2. 



Fig. 1. Ordinates represent logarithms of the number of particles outside the 



leucocytes in 0.02 c. mm. of the suspension. Curves show that the actual rates 



of ingestion of the quartz and carbon were nearly equal. Quartz, being, heavier, 



... , . . , , „ ^, , . K carbon 1.06 



collides more often with the cells. The corrected ratio, — =~rir^ = 3, 



K quartz 0.36 ' 



shows that carbon is taken up 3 times as readily as quartz. Two concentrations 



of both quartz and carbon were used, the higher concentration being twice the 



lower. See Table II. 



Fig. 2. Ordinates and abscissae as in Fig. 1. Curves showing the rates of 



ingestion of quartz and carbon particles. If the experimental points for quartz 



are accurate the initial K = 0. Assuming that the first two points on the quartz 



, , , , . . . , . K carbon . 



curves are erroneous, as seems most probable, the initial ratio, ^z- , is seen 



' f , , J. quartz 



to be at least > 1. Even interpreting the curves thus in favor of the quartz, the 

 corrected ratio is 2.8, showing that the carbon is taken up at least 2.8 times as 

 readily. Two concentrations (in the proportion of 1 to 2) of both quartz and 

 carbon were used. 



