A great many of the Non-traumatic Joint Affections are caused by acute exanthematous fevers and other infectious diseases. With metastatic or bacterial affections of the joint there is almost always at some stage exudation into the joint cavity. The changes which take place and the prognosis depend mainly on the nature of this exudation. In most cases of arthritis due to whooping-cough, dysentery, ague, influenza, and rheumatic fever it is mainly serous. In cases of measles, pneumonia, scarlet fever, diphtheria, typhus, typhoid, mumps, and erysipelas the exudations vary considerably, and are sometimes mainly serous, sometimes mainly purulent, but usually something between, the two extremes, i.e., serofibrinous or seropurulent. Those forms of arthritis which have their origin in the urinary tract, due to gonorrhoea or the use of dirty instruments, always vary very much. They are sometimes monarticular, sometimes polyarticular, and may be purely serous, serofibrinous, purulent, or even phlegmonous, should the process immediately become purulent in the capsule and pericapsular tissues. In cases of smallpox, glanders, puerperal fever, septicaemia, and pyaemia, the exudations in the joints are often more freely purulent.

The nature of the primary disease thus gives us a clue, though not a very certain one, as to the character of the exudation, an important feature in the prognosis. In an advanced case of pyaemia, even when abscesses occur in the neighbourhood of the inflamed joint, it may happen that the exudation is purely serous and that it is quickly and entirely absorbed. On the other hand, we all know what serious effects acute rheumatism may have on the joints owing to infiltrations, hyperplasia, contractions, and morbid changes in the cartilage and bone.

As far as the purely serous exudations of metastatic or bacterial inflammation are concerned, they cause no fever, little swelling, but little visible redness, or pain, slight infiltration in the capsule, and do not generally produce a position of contracture. In such cases there is every chance of complete absorption and recovery. A metastatic serous affection of a joint is not treated so long as the primary disease causes the patient to have any fever. When the fever is over the exudation has often been absorbed, and the power of movement, which for the time is very limited, or even appears lost, is soon restored by massaging the slightly infiltrated capsule and by means of passive movements.

The freely purulent or phlegmonous forms of arthritis are the direct cause of fever and disturbances of the general health as well as of marked redness, infiltrations, and considerable swelling in and around the joint. Tenderness on pressure over the joint and pain on movement are very marked, and, by reflex action, the patient keeps the joint fixed in the position representing the maximum capacity of the cavity. A permanent contracture is frequently developed, and a doctor always gives up hope of complete recovery in cases of free purulence. He must be glad if by means of incision, drainage, and antiseptic douching he can prevent the pus damaging the synovial membrane, capsule, ligaments and cartilage - in other words, if he can procure a joint which shows any signs of recovery without anchylosis and of a moderate functional power in the future. When the inflammatory processes are really over and the joint has healed, even in hopeful cases it is surrounded by hyperplasia, which quite disguises its shape, the capsule has lost its elasticity, shortenings of the muscles make the chances of curing the contracture small, and the joint becomes a life-long source of pain, especially susceptible to changes in the weather. Often many years elapse before, by daily use of the joint and by nature's own work of repair, power of movement is acquired, limited no doubt, but the greatest of which the joint is capable.

The symptoms and prognosis of serofibrinous and seropurulent inflammations of joints vary according to the nature of the exudation, which is sometimes more serous and sometimes mildly purulent.

Even though the prognosis of an arthritis depends largely on the nature of the exudation, there are also other points of very great importance, among them the patient's age, his general health, and - I lay special emphasis on this point - his energy and determination in carrying out the treatment.

Though it may be necessary during severe fevers with purulent metastases in the joints to postpone massage and passive movements, until the fever is over and the joint healed, both from the inflammation and surgical operations, I wish to point out that it is a grave mistake on the other hand not to begin this treatment as soon as it can be done. It must not be forgotten that the sooner frictions (which are always the most important manipulations in these cases) are begun, the less completely are the infiltrations and hyperplasia organised into connective tissue, and the sooner these are absorbed and the earlier movements begun the less conspicuous are the changes which result from lengthy immobilisation. Among doctors, without a doubt, the mistake of delaying too long in beginning massage and gymnastics after purulent inflammatory processes is commoner than that of beginning too soon.

The tubercular and syphilitic affections of joints deserve a special place among infectious diseases with regard to treatment, and massage and gymnastics are here of comparatively little importance.

Most medical practitioners agree that Tubercular Affections of Joints should not be treated by massage and gymnastics, and I too am of this opinion with regard to all those cases in which tuberculosis is actually going on in the joint. In one-fourth or one-third of the total number of cases this process begins in the synovial membrane (Schuller), and one can easily imagine that especially in these cases massage might aid the spread of infection. In later stages of tubercular joints purulence often contra-indicates massage.

On the other hand, it is my opinion, grounded on my own experience and on that of others, that by means of massage and gymnastics one can often very considerably increase the power of movement in joints where there has been tuberculosis, but which have not been destroyed and in which a certain power of movement is still found.

The Syphilitic Affections of Joints vary endlessly in their pathological anatomical conditions. There is no reason to massage the serous, subacute, and generally multiple synovitis which sometimes appears in the secondary stage and entirely disappears with anti-syphilitic treatment. Syphilitic osteitis, periostitis, osteomyelitis, and the carious, often purulent, arthritis occurring in congenital syphilis should also receive anti-syphilitic treatment. The gum-mata and chronic syphilitic inflammatory processes which frequently appear, often with fluid in the capsules of joints during anti-syphilitic treatment, probably recover more quickly with than without massage (Falkson). Massage is contra-indicated later on if there is necrosis or purulence.