Arthritis deformans has unfortunately been called by several names besides the descriptive term which, in the present state of our knowledge, is the most suitable for it. We do not know its cause. We do not well understand even the predisposing factors in its causation. Hence, the term arthritis deformans, which declares simply that it is an inflammatory condition of the joints producing deformities, exactly fits it. It has often been spoken of by such names as "rheumatic arthritis," or "rheumatoid arthritis," and, above all, by the unfortunate term "rheumatic gout." Many of the worst suggestions that attach to the word rheumatism are founded on these ill-chosen designations. Arthritis deformans was supposed to be connected with rheumatism or with gout, or perhaps to be due to a combination of the two. In a majority of the cases there is no history of either true gout or rheumatism to be obtained from the patient, and where a rheumatic or gouty history does occur, it is either quite indefinite or it is clear that arthritis deformans developed in a gouty or rheumatic subject, that is, following genuine gout or rheumatism, just as it might develop in any other individual without any causal connection between it and the other affections.

Supposed under the old theory to be a constitutional, probably a blood disease, patients who saw the ugly, crippling deformities produced by it and {422} then heard the word rheumatism used in connection with it were prone to think of this as the terminal stage of all the severe rheumatic conditions. As a matter of fact no evidence that we have shows that the disease has any connection with chemical modifications of nutrition or metabolism; nor, above all, has the so-called uric acid diathesis or any other superacidity of the blood any etiological connection with it. It has always seemed to me to be clearly a nervous arthropathy, as the lesions are almost without exception more or less symmetrically distributed. The joints that suffer are commonly the smaller ones in corresponding positions on opposite sides of the body, and they run a definite atrophic course sometimes with the preceding phase of hypertrophy that is so characteristic of the trophic lesions of an affection produced by a disease or defect of the nervous system. This symmetrical distribution constitutes the best possible evidence that arthritis deformans is not a nutritional disease and, above all, is not due to chemical changes in the blood.

The affection exists in at least three forms and there is a growing persuasion that there are even more varieties of it that will have to be separated by clinical observation.

There is a good study of the three types of the disease in Guy's Hospital Reports, Vols. 56-57, London, 1902. The article is entitled "Acute Rheumatoid Arthritis," but there seems no reason for applying the word rheumatoid to the group, especially since there is no proved connection with rheumatism and no similarity, except in the case of acute deforming arthritis in which at the beginning it may be difficult to differentiate the two affections.