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The Influence of Temperature on Phagocytosis. 
By J. C. G. Lepincuam, M.B., B.Sc., M.A., Assistant Bacteriologist, 
Lister Institute, London. 
(Communicated by Dr. C. J. Martin, F.R.S. Received November 18, 1907,— 
Read February 27, 1908.) 
Recent work has shown that the phagocytosis of micro-organisms is a 
complex phenomenon, involving at least two factors, viz.: (1) the sensitisa- 
tion of the micro-organism by the opsonin of the blood serum, and (2) the 
phagocytic act of the polymorphonuclear leucocyte. The latter function has 
been known for many years to be markedly influenced by temperature. It 
appeared desirable, however, to ascertain whether, by the modern quantita- 
tive methods employed in opsonic work, some definite relationship could be 
found to subsist between degree of temperature and degree of phagocytosis. 
In the first set of experiments no attempt was made to separate the respec- 
tive functions of sensitisation, and amceboid activity of the leucocyte. Both 
actions were allowed to proceed simultaneously. 
Consequently, in Series I the leucocytes were put in contact with fresh 
serum and micro-organisms (staphylococci), and incubated together at 
different temperatures for the same period of time. Thereafter the number 
of cocci taken up per leucocyte was calculated on stained films in the 
usual way. The Staphylococcus aureus employed was an old laboratory strain. 
Series _—Experimment L. , 
Cocci per leucocyte with incubation periods. 
‘Temperature. = ahs 
15 mins. 30 mins 45 mins 
43° C 15 °4 30 30 + 
37 L3e2Z 23 25 
18 Sali 3°3 1229 
It will be seen that at a temperature of 18° C. the degree of phagocytosis 
for 30 minutes is not appreciably greater than that for 15 minutes. There 
is, in fact, a prolonged latent period. This was further brought out in the 
next experiment, where the temperature remained constant (18° C.) while 
the incubation periods varied. 
Experiment IT. 
Temperature. Incubation period. Cocci per leucocyte. 
18° C. 15 mins. Ze9 
18 30 3°8 
18 45 2 
18 1 hr, ONT, 
18 1 hr. 15 mins. 12 °7 
18 1 hr. 30 mins. 19 “2 
