estimate the comparative phagocytic capacity of tv/o animals 

 without- taking into consideration not only the white count of 

 the blood but also a differential determination in order to ob- 

 tain the number of neutrophile leucocytes, the cells most com- 

 monly concerned in the phagocytosis of bacteria. 



Even by this method of determining a more exact measure 

 of phagocytic capacity, no account is, or can be, taken of the 

 tremendous phagocytic powers of the "fixed" cells, j.ietchnikof f 

 (37) first pointed out that these cells pla^r an important role 

 in resistance, and in a more recent investigation Bartlett and 

 Ozaki (8) demonstrated that the phagocytic capacity of the 

 "fixed" cells, of ten reveals a comoensatorjr increase whenever 

 there is an exhaustion of tne circulating phagocytes. it wouM 

 therefore seem necessary to balance any demonstrable decrease 

 in phagocytic activity of the blood against the possibility 

 tnat this loss in effectiveness might be compensated for by in- 

 creased activity of the infinitely more numerous "fixed" cells. 



There remains one other factor that should be considered 

 before concluding that a lowered opsonic index, secured accord- 

 ing to the method of '.Vright, indicates an absolute depression 

 in phagocytic defense. It is reasonable to suppose that in con- 

 sequence of the rapid destruction and replacement of neurtophile 

 leucocytes daring infection tiiat these cellular elements are 

 younger in infected than in normal animals. Hektoen (38) sug- 

 gests that it is possible to account for the increased phago- 

 cytic activity which Tunnicliff (39) demonstrated in exudates 



(56) 



