THE PROTECTION OF MICRO-ORGANISMS

"'If ever there was a romantic chapter in pathology, it has surely been that of the story of phagocytosis.' So said the late Lord Lister in his presidential address to the British Association in 1896, and so we, with equal fervor, say today when many more pages of the story have been turned over."¹ The term "phagocyte" was coined to designate the ameboid cells capable of seizing and digesting micro-organisms, red blood corpuscles and other formed structures. The property of phagocytosis is an attribute of a considerable number of different varieties of cells besides the more familiar representatives present in the circulating blood and tissue fluids. Zinsser² states that among the fixed cells of the body it is probable that phagocytosis may be carried on by cells of many different origins, though the identification of cells in tissues is often a purely morphologic problem, and therefore fraught with