In fact, we are coming to recognize that diseases of the joints, like diseases of the nervous system, are among the frequent results of any and all of the acute infectious diseases or fevers; and we now trace from fifty to seventy-five per cent of both joint troubles and degenerations of the nervous system to this cause. Two-thirds, for instance, of our cases of hip-joint disease and of spinal disease (_caries_) are due to tuberculosis. The puzzling problem now before pathologists is the sorting out of these innumerable forms of joint inflammations and the splitting off of those which are clearly due to certain specific diseases, from the great, central group of true rheumatism. Most of these joint inflammations which are due to recognized germs, such as the pus-organisms of surgical fevers, tuberculosis, and typhoid, differ from true rheumatism in that they go on to suppuration (formation of "matter") and permanently cripple the joint to a greater or less degree. So that there is probably a germ or group of germs which produces the swift attack and rapid subsidence and other characteristic features of true rheumatism, even though we have not yet succeeded in sorting them out of the swarm. So confident do we feel of this, that although, as will be shown, there are probably other factors involved, such as exposure, housing, occupation, food, and heredity, yet the best thought of the profession is practically agreed that none of these would alone produce the disease, but that they are only accessory causes plus the micrococcus. In practically all our modern textbooks of medicine, rheumatism is included under the head of infections.