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in great numbers in the blood—the Spirochaeta Obermeieri—closely resembling the innocuous Spirochaeta Cohnii or plicatilis found in the mucus of the teeth. During the intervals between the febrile attacks none of these organisms can be detected in the blood. Outside the body they show active movements at a temperature of 60" or 70", become languid at blood heat and die at fever heat. The pyrexia therefore of the patient is supposed to destroy the organism, which then breaks up into a number of minute granules, some of which may constitute the spores from which fresh crops of the organism may develope. If blood containing spirochsetse is taken from a patient during the stage of pyrexia and human beings or monkeys inoculated with it, the disease can be reproduced, but not by blood taken during the intervals between the febrile attacks. Injections of the blood into other animals such as dogs, rabbits and guinea-pigs were always without result. All attempts to cultivate the organism outside the body have as yet been unsuccessful, so that we really know very little of its history.
Here again we have a disorder associated with a bacillus, the organism disappearing and reappearing from the system and the blood of the infected animal being intermittent in its power of communicating the disease to other animals.
Perhaps few disorders of the human frame have greater interest attached to them than those associated with tubercle, and when we remember that one-seventh on an average of the deaths of human beings result from pulmonary tuberculosis, the importance of any fresh light shed on this disorder, or the discovery of any new fact can not easily be overestimated. The discovery, then, by Koch in 1882 of a bacillus in the tubercular diseases of man and animals has necessarily attracted a good deal of attention and led
