Two years ago, when the toxic theory of the causation of insanity was attracting attention in this country, I made a series of observations on the blood of acute recent cases of insanity with the object of ascertaining whether organisms were ever present. In no case, with the exception of one of general paralysis, did I ever find an organism in the blood. It occurred to me, however, that if I could make an aseptic necrotic area subcutaneously, the serum and pus in such an area would be a suitable nidus for the growth of organisms circulating in the blood, and that by aspirating the serum and pus and placing it in suitable nutrient media one should be able to grow such organisms, if present. Acting upon this theory, I took a case of acute mania—an adult woman—and, with antiseptic precautions, injected into the soft tissues of the flank 2 c.c. of turpentine.(1) An abscess formed, and on the third day after the injection I aspirated some fluid, consisting of blood-serum and pus. A couple of drops of this fluid were then added to each of four tubes containing 8 c.c. of sterile nutrient broth. These tubes were incubated for forty-eight hours, when they showed slight turbidity, and upon microscopical examination the broth was found to contain a pure growth of a small diplo-bacillus.