It is now a universal belief that a number of diseases owe their origin to the invasion of the body by specific micro-organisms, and the true etiology of a class of affections of the skin is based on this belief. Hence the most successful treatment has been the application of that which would kill the invading microbe—without injuring the skin structure. The skin is constantly being invaded by micro-organisms which produce disease when the patients are physically below normal, and, to combat these infections more successfully, constitutional treatment has been found necessary.
All this was realized, but until Leischman, in 1902, gave to the profession his method of measuring phagocytic activity the progress of the treatment could be noted clinically only. Sir A. E. Wright and his associates, Leischman and Douglas, demonstrated by a series of experiments, based on the theory of phagocytosis, that there are properties in the blood
VARNEY HR. OPSONIC THERAPY IN SKIN DISEASES.. JAMA. 1907;XLIX(4):316-320. doi:10.1001/jama.1907.25320040028002h