460 



PHAGOCYTOSIS OF SOLID PARTICLES. I 



diameter) were used for incubation, and there was more irregular 

 stirring by the air bubble which moved up and down the rotating 

 tube. Under these circumstances the explanation offered for the 

 different rates of ingestion of the three suspensions seems satisfactory. 

 The data used in calculating R are given in Table V. The velocities 

 obtained for each group were the weighted averages of all the separate 

 velocities in the group, not the velocity corresponding to the average 

 diameter. The group diameters of the two larger suspensions are the 



TABLE V. 



Chances of Collision of Leucocytes with Three Sizes of Quartz Particles as Prepared 

 in Experiments 5 and 6. 



average diameters of the group. For the smaller suspension they 

 are calculated from the average velocity. The difference in the 

 result is too small to have any appreciable effect. The latter method 

 is more accurate because it is the square of the diameters which enters 

 into the equation. The error in calculating must be larger for the 

 smallest suspension because in this case the group velocities nearly 

 coincide with the velocities of the groups of cells. The true chance 

 of collision is, therefore, somewhat higher than the calculated figure. 

 This could be avoided by the use of calculus, treating the frequency 



