BY R. GREIG-SMITH. 



687 



lite nature of the fluid in which phagocytosis takes place. — 

 As a rule the corpuscles and bacteria are suspended in normal 

 saline varying from 06% to 9 % of sodium chloride. Some- 

 times, as in the case of tuberculopsonisation, the corpuscles are 

 suspended in - 85 % saline and the bacteria are distributed in 

 0*1 %. It is probable that different percentages of salt will exert 

 some influence upon the extent of opsonisation and therefore upon 

 the rate of phagocytosis. It is further to be expected that a 

 slowing of the rate of ingestion will induce a more regular 

 englobment. In the following, an attempt was made to see in 

 which direction further experiments should be made. 



Corpuscles in 0*6 % saline; 

 bacteria in 



20 counts. 



Total 100 

 count. 



1. Saline, 01% 



2. Saline, 0*1% 



S3, 103, 91, 60, 58 

 69, 79, 86, 69, 99 

 99, 118, 109, 108, 98 

 51, 53, 53, 50, 40 

 93, 36, 32, 98, 90 

 39, 40, 69, 67, 64 



395 



402 



3. Saline, 0-85% ..., 



4. Citrate, 5%. 



532 

 247 



5. Citrate, 1-0% 



350 



6. As No. 1, but with dead bacteria.... 



285 



The increase of the saline content has augmented the phago- 

 cytosis both in the common salt and the citrate tests. The 

 citrate made the ingestion slower, and in No. 4 it was compara- 

 tively regular, although perhaps not more so than No. 3 which had 

 the high common salt content. This table shows very well the 

 differences which usually occur in the counts. Although in the 

 subsequent experiments the counts were carefully scrutinised, I 

 shall not record them for reasons which will become apparent. 



I was informed by Dr. Freeman, in Sir A. E. Wright's labora- 

 tory, that if a typical count is plotted, making the number of 

 bacteria ingested by each leucocyte the abscissse and the numbers 

 of leucocytes the ordinates, the curve should gradually rise to a 

 maximum and as gradually fall. 



These and many other counts were examined in this manner, 

 but in no case was the curve of this nature. As a rule the zero 

 was high, from which the curve rose slightly to a maximum and 



