512 Mr. G. Dean. On the Nature of the [July 8, 
One method employed was that of adding a measured quantity of a 
microbial emulsion to a certain volume of serum which had been heated to 
60° for 20 minutes, allowing this to stand for varying periods at 37° C., then 
centrifugalising and ascertaining whether the centrifugalised cocci were 
capable of being taken up by the leucocytes. 
Experiment.—0'5 c.c. of an emulsion of Staphylococcus (= 4 agar tube) was added to 
5 c.c., of a normal horse serum, which had been heated to 60° C. for 20 minutes. The 
cocci, separated by centrifugalisation and made into a suitable emulsion with normal salt 
solution, were compared with normal fresh cocci in Wright’s tubes. 
Cocci counted in 
22 leucocytes. 
No. of ingested 
Vol. cocci per leucocyte. 
Emulsion of fresh cocci ............... 1 
+ Heated normal horse serum ......... i } 4 
+ Normal horse leucocytes............... 1 
Emulsiofi of prepared cocci............ 1 
+ Normal salt solution’ y.ices-aeeoc ee 1 } 60 
+ Normal horse leucocytes................ i) 
Experiment.—0'1 c.c. of an emulsion of Staphylococcus (= 1/10 of an agar tube) was 
mixed with 1 ¢.c. of normal human serum, which had been heated to 60° C. for 20 minutes. 
This mixture was placed for 15 minutes at 37° C., and then the cocci were centrifugalised 
from the mixture and made into a suitable emulsion with normal salt solution. 
These prepared cocci and fresh cocci were used for a comparative test in capillary tubes 
in the ordinary manner. 
Cocci counted in 
22 leucocytes. 
No. of ingested 
Vol. cocci per leucocyte. 
OVESHACOCCL, <i ee sn seal oc Neceee eels 1 
+ Heated normal serum .................- 1 } 0 
+ Leucocytes (human).................000 1 
prepared: COCCl pense eee cance: alse i 
-+- Normal salt solution: (22540 .cc.8520-0 63 il 60 
+ Leucocytes (human),...............00008 1 
A large number of similar experiments which need not be detailed here 
were done with concordant results; in several cases a smaller proportion of 
serum to bacterial emulsion was used. 
Such results were obtained in the cases of normal human serum (four 
samples), horse serum, goat serum, rabbit serum, guinea-pig, and rat serum. 
Normal horse serum which had been kept for four years still retained this 
property. 
These experiments prove that though the results obtained by using Wright’s 
method seem to demonstrate that the substance capable of preparing the 
