690 



OPSONI3ATION PROM A BACTERIAL POINT OF VIEW, ETC. 



Experiments were also made with the same suspensions per- 

 mitting the phagocytosis to proceed for 30 minutes at 37°. The 

 results, however, were very irregular, and there appeared to have 

 been a considerable amount of intracorpuscular digestion. The 

 experiment shows that a suspension of bacteria in 0*4% to 0*8% 

 citrate gives very concordant counts, and much might be gained 

 by using this salt should a better not be found. 



The effect of glycerin was then tried. A preliminary experi- 

 ment showed that it was not advisable to suspend the corpuscles 

 in glycerin alone on account of the haemolysis of the erythrocytes. 

 They were therefore suspended in the citrate-saline of the previous 

 experiment. 



Bacteria suspended in glycerin. 



Cocci per leucocyte. 



0'2 per cent. 



9 9 



0-4 



7-0 



0-8 



6 4 



12 



7'5 



1-6 ;, 



7-6 



20 



6 3 



The glycerin had a distorting action upon the leucocytes and 

 appeared to hinder the regular ingestion of the bacteria. There 

 was nothing to recommend the glycerin over the citrate. 



A shorter period of incubation was then tried with bacterial 

 suspensions containing glycerin and citrate. As in all the other 

 experiments, unless otherwise stated, the temperature of incuba- 

 tion was 37°. An extension of the experiment was made in the 

 direction of keeping two of the tests at room-temperature (23°) 

 for 30 minutes. 



Bacteria 



Cocci per leucocyte. 



suspended in 



Duration of phagocytosis. 



Glycerin, 8 p. cent. 

 Citrate, 0*6 p. cent. 



2 min. 

 32 

 1-9 



5 rnin. 

 3-8 

 25 



10 min. 

 41 

 3 2 



15 min. 30 min. at 23° 

 49 4-5 

 33 29 



The most regular of the counts were those which had been 

 incubated for 15 min. An interesting part of the experiment, 

 however, was the phagocytosis at room-temperature, viz., 23°, 



