1. Bovine tuberculosis is no longer a factor of any significance in the causation of bone and joint tuberculosis among adults in Ontario.

2. Adequate treatment of bone and joint tuberculosis demands adequate provision for rest as well as adequate provision for surgery.

3. Prognosis is affected favorably by two factors in particular:

(a) Adequate treatment of abscesses, so as to prevent secondary infection of bone,—the existence of an uncontaminated tuberculous abscess need not affect the prognosis adversely.

(b) Freedom from multiple lesions of tuberculosis in the body.

4. Secondary infection of various joints has the following effects:

(a) Of the spine renders the prognosis almost hopeless;

(b) Of the sacro-iliac joint and hip renders the prognosis poor;

(c) Of the knee, ankle, or foot requires excision or amputation;

(d) Of the joints of the upper extremity greatly prolongs hospitalization.

5. Multiple lesions of tuberculosis are to be found in a high proportion of cases, as follows:

(a) Pulmonary tuberculosis in over 40 per cent.

(b) Multiple bone tuberculosis in almost 30 per cent.

(c) Genito-urinary tuberculosis in over 20 per cent.

The prognosis is affected adversely by the presence of these complications, their importance being in the order named.

6. More than one-third of all patients were free from multiple tuberculous foci. The percentage of arrested disease and the ability to return to work in these patients was high, especially in the cases of tuberculosis of the spine (80 per cent.) and of the knee (100 per cent.). The mortality rate was 13 per cent. and was usually due to secondary infection of bone, or to non-tuberculous disease.

7. Almost one-quarter of all patients had additional tuberculosis in other bones, or in the genito-urinary system, or in both, but not in the lungs. In these, the treatment has to be long enough to arrest tuberculosis throughout the body, and more than one operation is usually required. The incidence of return to work is much reduced and the mortality rate rises to about 20 per cent., due to the appearance of meningitis and of Addison's disease in addition to chronic suppuration and nontuberculous disease.

8. Over 40 per cent. of all patients had pulmonary tuberculosis, the most serious of tuberculous complications. When this is combined with other skeletal and renal foci the prognosis is very much worse than when pulmonary tuberculosis is the only complication, the incidence of arrested disease and of return to work in the latter being between 40 and 50 per cent., and in the former between 12 and 20 per cent. The mortality rate rises from 38 per cent. in the latter to between 44 and 80 per cent. in the former, the outstanding causes being miliary tuberculosis, meningitis, and pulmonary tuberculosis.

9. Tuberculosis of the spine was arrested in 88 per cent. of patients treated by spine bone graft, but in 26 per cent. the arrest of the systemic disease was delayed or entirely prevented by tuberculosis elsewhere in the body.

10. The best results are to be obtained by treating bone and joint tuberculosis first by rest and by controlling other tuberculous foci in the body; then by operation to secure bony ankylosis of t.he affected joint, because the results following this are superior to those obtained by the fibrous ankylosis or unstable joints which so often mark the end result of non-surgical treatment.