480 



PHAGOCYTOSIS OF SOLID PARTICLES, n 



tained carbon is plotted as ordinates in Fig. 8. In 26 per cent serum 

 nearly all the cells had clumped up in 15 minutes, after which they 

 began to creep out of the clumps until at the end of 4 hours nearly 

 one-half the original number was again free. In pure 0.9 per cent 

 sodium chloride (control) there is least clumping and least phago- 

 cytosis. Similarly, in 26 per cent serum where clumping is most 



Number of Cells 

 Z 



flours 



Fig. 7. Ordinates and abscissae as in Fig. 6. Curves illustrate the effect of 

 serum and an equivalent concentration of Ringer's solution on the clumping of 

 leucocytes. After the first rapid agglutination, the cells begin to creep out of 

 the clumps again. 



rapid, phagocytosis is also most rapid. Part of the effect of serum 

 is due to its calcium, since the same amount of Ringer's solution also 

 increases both phagocytosis and clumping, though to a lesser degree. 

 The small percentage of free cells containing carbon at the end of the 

 1st hour (Fig. 8) is probably due to the more rapid clumping of such 

 cells, as already described (Fig. 6). 



