Despite the increasing literature on the subject of rheumatoid arthritis, the ultimate nature of the disease is far from clearly established, and even at this date we do not positively know just what affections of the joints should be grouped under the name. Nothing so clarifies the nosographic atmosphere as the discovery of causes—only through causal knowledge are we able to separate diseases that are similar and to assign to them a definite place in our systems. How easy it has become for us to define typhoid fever, diphtheria, and malaria, since their etiology has been determined. As we are still unable to point out the true cause of rheumatoid arthritis, it would, I believe, be better, following the example of Virchow, Garrod, and others, to use the phrase arthritis deformans, as that expresses the most prominent symptom and is non-committal on the score of pathogenesis.
Morbid anatomy.
—The lesions