518 Mr. G. Dean. On the Nature of the [July 8, 
volumes of normal horse serum, centrifugalised, and the supernatant fluid, which was 
then free from all organisms, tested for phagocytic power, normal washed horse leucocytes 
being used. 
Average number of cocci 
per leucocyte in 22 poly- 
morphonuclear leucocytes. 
Original serum yo..3.iccces aye hedh ee ee eee cc on seen 40 
Serum through which prepared cocci had been passed ............ 30 
Serum through which fresh normal cocci had been passed ...... 2°3 
The repetition of this experiment with freshly prepared material gave the following 
numbers :— 
Average number of cocci 
per leucocyte in 22 poly- 
morphonuclear leucocytes. 
Freshly prepared :serum (297 24.4..02- + ak coke estes eee see 35+ 
Ditto through which the prepared cocci had been passed......... 27 
Ditto through which fresh normal cocci had been passed......... 2 
In carrying out these experiments care must be taken that excess of sub- 
stance is not left adhering to the cocci, in which case it may diffuse out into 
the surrounding fluid. See previous experiments. To obviate this happening 
the prepared cocci must be rapidly washed in normal salt solution. 
These experiments seem to show that the cocci occupied by the substance 
from immune serum are incapable of taking up much of the substance from 
normal serum, whereas fresh cocci are capable of removing a large proportion 
of the substance. 
Tests of the Serum of Animals Immunised against the Streptococcus, Typhoid 
and Dysentery Bacill. 
Streptococcus. 
The serum of three horses immunised against many races of streptococci 
was examined with the following result :— 
Cocci counted in 
22 leucocytes. 
No. of ingested 
Vol. cocci per leucocyte. 
Horse 1— 
Washed leucocytes of horse ............s.eseeeeeees 1 
+ Serum Of IMMUNE NOSED sce. csscesseses sce sese >: 1 } 9 
+ Emulsion of streptococcus from agar ............ 1 
Washed leucocytes of horse .............s:seseeee8 1 
+ Serum of normal horse); .::.0.5....:0s-s-seee ses 1 } 4 
+ Emulsion of streptococcus from agar............... 1 
Horse 2— 
Washed leucocytes of horse serum .............+. 1 
+ Serum Of Immune horse 32h .21cssscedes ese sneeeees 1 f 12 
+ Emulsion of streptococcus from agar ............ 1 
