There are three essential factors concerned in bacterial phagocytosis on which chemical substances may act so as to increase or depress phagocytic activity, namely (1) the leukocytes, (2) the opsonins, (3) the bacteria. The influence of various chemical substances on phagocytosis might be of great importance in bacterial diseases in which various drugs are now used without knowledge of their effect on the processes which produce immunity. A review of the action of chemical substances on phagocytosis with a study of the influence of some extensively used therapeutic agents has been made by Arkin.1 From the results it appears that the action of chemical substances on phagocytosis varies with their chemical composition and their pharmacologic action. Substances which have an inhibitory effect on oxidation, such as chloroform, ether, morphin, potassium cyanid, alcohol, etc., all depress phagocytosis.
That the oxidative processes play a rôle in phagocytosis is evident because sodium