Influence of the Constituents of a Bacterial Emulsion, etc. 321 



opsonic index. With this end in view we have sought answers to the following 

 questions. 



What is the Effect of Removing Detritus from a Bacterial Emulsion and of 

 Adding it to such an Emulsion ? 



Experiment 1. — An emulsion giving with the usual technique a count of 

 0-5 per cell in 15 minutes was centrifugalised ; the supernatant fluid 

 •containing much detritus was pipetted off and an equal volume of saline 

 added and shaken up with the deposit. The resulting emulsion then gave 

 a count of l - 9 per cell. Thus by removing some of the detrihos the phagocytosis 

 loos increased about four times. 



Experiment 2. — Two phagocytic mixtures were made, consisting of equal 

 volumes of washed corpuscles ; suspension of washed bacilli ; serum ; and, in 

 the one case, saline, and in the other, suspension of baeillary detritus. 



The following were the counts : — 



(1) (2) 

 With saline. With suspension of detritus. 



1- 61 0-62 

 Similar experiments gave the following counts : — • 



(1) (2) 



(a) 4-92 317 



(b) 2-05 1-40 



(c) 1-65 0-64 



Thus — and this is the converse of the conclusion above arrived at — the 



addition of detritus causes a well marked reduction in the phagocytosis. 



Is this Reduction Due to an Effect Exerted by the Baeillary Detritus on the 

 Phagocytes, or on the Serum ? 

 Experiment 2b. — Three phagocytic mixtures were taken — equal volumes of 

 corpuscles, suspension of washed bacilli, and — 



(a) In the first mixture saline and serum. 



(b) In the second, suspension of detritus and serum. 



(c) In the third, two volumes of mixture of equal volumes of the suspension 

 of detritus and serum, previously incubated for 20 minutes. 



The following were the phagocytic counts : — 



(a) (b) (c) 



2- 05 140 0-37 

 And a similar experiment gave 



1-65 0-64 0-27 



