454 



PHAGOCYTOSIS OF SOLID PARTICLES. 



The phagocytic mixtures were prepared as follows: 0.2 cc. of washed leucocyte 

 suspension in 0.9 per cent sodium chloride, plus 0.15 cc. of quartz suspension in 0.9 

 per cent acacia plus 0.1 cc. of fresh serum plus 0.05 cc. of m/10 phosphate mixture 

 ([H]""" = 3 X 10~^) plus 0.05 cc. of 4.5 per cent sodium chloride. The acacia was 

 added to prevent agglutination of the quartz. The phosphate helped to main- 

 tain the hydrogen ion concentration equal to that of blood serum. Frequent 

 colorimetric measurements of [H]+ at the close of the experiments showed no ap- 

 preciable change in reaction from the original. Without serum there is very little 

 phagocytosis. 



TABLE III. 



Comparison of Theoretical and Experimental Rates of Phagocytosis of Three Sizes 



of Quartz Particles. 



Average diameter of particles. 



(Minimum. 

 Maximum. 

 Average . . . 

 Chances of collision 



Experiment 1 

 (Fig. 5) 



Experiment 2 

 (Fig. 6) 



Average per cent j Assumed, 

 of error \ Expected 



K. 



Average per cent f Assumed., 

 of error \ Expected . 



Ratio. 



1:0.41:0.51 

 (Theoretical.) 



1:0.42:0.64 

 (Experimental.) 



1:0.87:0.58 

 (Experimental.) 



1:0.64:0.61 

 (Average exper- 

 imental.) 



The above mixture was incubated at 37°C. in small glass-stoppered vials 6 mm. 

 in outside diameter, which were rotated about their horizontal axis once in 2 

 minutes. The speed of rotation was kept constant in any one experiment. Since 

 the tubes were so small and were held horizontal, there was very little stirring by 

 the air bubble included at one end of the tube. Counts of the number of particles 

 outside the phagocytes per 0.02 mm.^ of solution were made at intervals. The log- 

 arithms of these counts were then plotted as ordinates against time as abscissas. 

 If phagocytosis follows the laws of monomolecular reactions these points should 

 lie on a straight line of slope K, where K is the velocity of the reaction. A sum- 

 mary of Experiments 1 and 2 is given in Table III and the experimental points 

 are plotted in Figs. 5 and 6. 



