WALLACE O. FENN 



461 



curves in Fig. 8 as normal frequency curves, but the resulting expres- 

 sion would be too difficult to work witti.^ 



Since the group chances of collision are not all equal in the same 

 suspension the chances of collision as a whole will tend to decrease 

 as those particles with the greatest R are taken up first. It can be 

 shown that R decreases most rapidly for the 4.63 /.t particles. The 

 ratios, therefore, increase. This ratio has been calculated for the 

 times in the experiment when the 4.63 /x particles are 50, 75, and 

 90 per cent ingested (Table VI). 



TABLE VI. 



Comparison of Theoretical and Experimental Rates of Phagocytosis of Three Sizes 



of Quartz Particles. 



In Figs. 10 and 11 are plotted the experimental points in Experi- 

 ments 5 and 6 respectively, and the results are summarized in Table 

 VI. For comparison, the initial and the total K's have been calculated. 

 The latter are calculated by the method of least squares and the former 

 directly from the experimental figures. The agreement between these 

 experimental ratios and the expected ratios seems remarkably good 

 when the many complicating factors involved in this type of experi- 

 mentation are taken into consideration. 



^ The writer wishes to express his gratitude to Professor R. G. Wilson, Massa- 

 chusetts Institute of Technology, for information on this point and also for valuable 

 criticism of this work. 



