The title of this paper, if liberally interpreted, might lead one to discuss the differential diagnosis of a great variety of joint affections that present certain features resembling those of true rheumatism and which might, therefore, be called rheumatoid.
Rather arbitrarily, perhaps, I shall narrow the discussion and not consider such conditions as sarcoma of the joint, ordinary monarticular tuberculosis, sprains and other traumatic arthritides, though, as is well known, there is often a necessity for differentiating between rheumatism and these conditions. Nor shall I do more than mention the arthritides occurring in connection with definite infectious diseases, such as scarlatina, pneumonia, epidemic meningitis, septicemia, pyemia, etc. Here diagnosis is comparatively easy if the existence of the primary disease is known, though in some instances, e. g., during convalescence from a mild and ambulatory scarlet fever, diagnosis may not be simple.
In epidemic meningitis, too, joint pains with articular and