1907.| The Influence of Temperature on Phagocytosis. 191 
Experiment V.—In this experiment the sensitisation was performed at 
18° C. for 20 minutes, and the same coccal emulsion was employed as in 
Experiment IV, so that the figures obtained are quite comparable. 
Temperature. Cocci per leucocyte. 
37° C. 6-2 
28 4, *2 
18 ; 2°6 
7 0°8 
Experiment VI.—A portion of the coccal emulsion was combined with 
serum at 37° C. for 20 minutes, and an equal portion combined with serum 
at O° C. for the same time. Leucocytes were then added, and the results of 
phagocytosis at different temperatures compared. 
Combination at 37° C. Combination at 0° C. 
Temperature. Incubation time. Cocci.' Temperature. Incubation time. Cocci. 
37° C. 15 mins. 121 Si ©: 15 mins. 8°8 
20 15 8°6 20 15 0°4 
The very great difference between the amounts of phagocytosis at 37° C. 
and 20° C. after combination at 0° C. offers a marked contrast to what 
obtains under the same conditions after combination at 37° C. The employ- 
ment of very thin coccal emulsions, however, and the prolongation of the 
period of combination with the serum, have the effect of equalising the 
amounts of phagocytosis at high and low temperatures even after low- 
temperature combination. 
Throughout the experiments which illustrate this point, thin coccal 
emulsions were combined with serum for long periods, and the mixtures 
required no centrifugalising before use. 
Experiment VII.—Combination at 37° C. for 45 mins. 
LEE = loys: 
Temperature. Cocci per leucocyte. 
3. 9°6 
18 8 ‘0 
Experiment VIII.—Combination at 37° C. for 2 hrs. 45 mins. 
loTy= 15 mime 
Temperature. Cocci per leucocyte. 
37° C. 15 ‘0 
18 14 °5 
Two further experiments similar to Experiment VIII gave ratios of 
12:°2:12°6 and 14:1:13°3 for the amount of phagocytosis at 37° C. to that at 
18° C. | 
