Roentgen-ray studies were made in all cases of the 400 in which there was any suspicion that there might be additional evidence discoverable by these means. One hundred and seventy-nine series of plates were made, ranging from one to twenty plates in any given series, and the percentage of positive findings justified omitting recourse to the roentgen ray in the absence of such suspicion.The total number of cases of arthritis studied was 400. One hundred and forty-seven cases, or 37 per cent., were studied with the roentgen ray. Forty-six cases, or 31 per cent. of the 147, gave positive roentgen-ray findings. The forty-six cases giving positive roentgenray findings constituted 11\m=1/2\per cent. of the whole series of 400 cases. In other words, making allowances for cases which may have been I desire to express obligation for the helpful cooperation of Lieut.