446 PHAGOCYTOSIS OF SOLID PAHTICLES. I 



The result was as follows: 



K = 0.22 

 (Counts refer to volumes of 0.02 mm.') 



K = 0.52 



The diameter of the orbits of cells and particles has been calculated 



V . 



from the equation Diameter = — j and is compared in the following 



irn 



tabulation with the average distance between cells and particles 

 calculated from the equation 



. J- 4. „ /Total volume of suspension ,7 



Average distance = */ i- = 37^ 



T No. of cells + No. of particles 



Cells. Particles. 



Average diameter 9.0 2.9 



Diameter of orbit at 19 revolutions per min 4.6 7.3 



" " " " 0.3 revolution " " 279 462 



These results show that the diameters of the orbits of cells and 

 particles at 19 revolutions per minute are small compared to the dis- 

 tances between them. It is, therefore, only due to the fact that the 

 laws of chance prevent all particles from being equidistant from each 

 other {i.e. 37)u) that there was any phagocytosis at all at 19 revolutions 

 per minute. In this case, also, when the cells are practically station- 

 ary, brownian motion probably plays some part in bringing particles 

 to the cells. Centrifugal force is another factor which would have a 

 very slight effect in causing collisions. It was calculated that at 19 

 revolutions per minute 12 per cent of the particles and 8 per cent of 

 the cells would be centrifugalized against the wall of the tube and that 

 it would take 21 minutes for a particle to overtake a cell 37;u distant, 



