be so severe as to interfere with the patient's earning a living, or if suppurative pyelo-nephritis or pyonephrosis develop, the kidney may be cut down upon and the calculi removed or the kidney extirpated. Care, however, should be taken that the other remaining kidney is competent, and not atrophied from previous disease or congenitally absent.

PERINEPHRITIC ABSCESS.

Etiology. Suppuration of the perinephritic tissues may result from traumatism or from extension of suppuration from the kidney, intestine (especially the vermiform appendix), liver, or spinal column. Burrowing downward of a perforating empyema has occurred.

Symptoms. As the disease is, properly speaking, a surgical one, but a brief description of the symptoms will be given. Pain and tenderness are present in the lumbar region. The pain is somewhat relieved by keeping the body immobile and by flexing the thigh. In rare cases the pain may be altogether referred to the hip-joint or to the knee. In the lumbar region there may be detected a tender, indurated mass which in the latter stages may yield a sense of fluctuation. The abscess may appear externally, or internal rupture in any direction may occur.

The constitutional symptoms are those of an internal abscess-chills, fever, and the gradual development of sepsis.

Treatment consists in opening and draining the abscess.

VI. CONSTITUTIONAL DISEASES.

ACUTE ARTICULAR RHEUMATISM; RHEUMATIC

FEVER.

Etiology.-Rheumatism may occur at any time of the year, but it is more common in the spring months. Heredity is traced in 25 per cent. of the cases. One attack predisposes to successive attacks, and relapses are common. No age is exempt. It is very common in children, and it may even be a disease of intra-uterine life. It occurs especially in those leading a life of exposure, and the exciting cause may be wet and cold or over-strain of a muscle or a joint. The disease is rare in the tropics.

Rheumatism at certain times assumes epidemic proportions, and when this is the case the clinical features are apt to vary.

The following theories of rheumatism have been advanced; no one of them has been satisfactorily proven :

1. The nervous theory, that rheumatism depends upon disturbances of the nerve-centres presiding over the nutrition of joints.

2. The lactic-acid theory, that rheumatism is due to the presence of lactic acid in the blood, due to some perverted tissue-change of muscle.

3. The uric-acid theory of Haig, that uric acid formed in the blood may be deposited in the joints by diminished alkalinity of the blood. It has been supposed that lactic and uric acid in combination might produce the lesions.

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4. The theory of microbic infection is based upon the generalization of the lesions, the involvement of the fibro-serous membranes so commonly involved in other known bacterial diseases, the constitutional predisposition seen in many patients, and the occurrence of occasional epidemics of the disease. No germ has yet been isolated, although experiments seem to confirm the theory of bacterial infection.

Symptoms.-I. General.-The onset may begin acutely with a chill and fever, or subacutely by shooting pains in the joints, malaise, and moderate fever. In rarer cases the joint-symptoms are the first symptoms observed.

The fever is rarely intense, usually under 103° F., and runs no typical course. Formerly its duration was from two to four weeks, but owing to improved methods of treatment it now rarely lasts more than from two to five days. In children the fever is but moderate, and it may even be absent. It is important to watch the temperature throughout the disease. A rise in temperature usually means a fresh invasion of joints, or some complication, such as endocarditis or pericarditis, while a fall generally implies a subsidence of the disease and modifies the therapy. The occurrence of hyperpyrexia will be noted later.

The pulse is full and dicrotic.

The urine is diminished, is of increased acidity and high specific gravity, and contains urates and an increased quantity of uric acid. Febrile albuminuria may be observed.

Cerebral symptoms are not seen except in cerebral rheumatism with hyperpyrexia or in over-dosing of salicylic

acid.

The blood in rheumatism becomes rapidly anæmic. In the majority of cases there occur drenching sweats of a peculiarly sour odor, and the skin may show sudaminal vesicles.

2. Inflammation of Fibro-serous Membranes.-The joints are almost regularly involved, giving a distinct clinical type to the disease. In children, however, joint-symptoms are regularly less marked than in adults, and may be absent altogether (the "abarticular" form). The lesion is a simple serous synovitis. The synovial membrane is hyperæmic; its cavity is filled with serum and flocculi of fibrin. There is no pus-formation. There are often similar lesions in the sheaths of adjacent tendons. There are pain, increased by motion, and tenderness of the affected joints. The extent and character of the swelling depend upon the amount of synovial effusion and the involvement of the adjacent tendon-sheaths. The skin over the joint is usually hot, reddened, and not infrequently is œdematous. These symptoms are less marked in children, who may only show some rigidity to passive motion of the joint, and a continued position of flexion which is especially marked in the knees, and appears to be due to inflammation of the sheaths of the hamstring tendons, the joints themselves escaping.

Characteristic of rheumatic synovitis are the great rapidity of its development and subsidence, the involvement of many joints by jumps (fresh articulations being involved while those first attacked are recovering), and the rarity of its attacking one joint alone. Monarticular rheumatism is so uncommon that a diagnosis of rheumatism should always be made with extreme caution. The larger joints are especially liable to be attacked, but the small joints of the hands and the feet may be involved. Any joint may be attacked, but the temporo-maxillary articulation is so rarely involved as to throw doubt on the diagnosis, should this joint be affected. Symmetry of involvement is rare, the disease differing in this respect from acute rheumatic arthritis. Pain and swelling often persist after the acute process has subsided, and there may be some stiffness from adhe

sions within the joint-cavity. An acute attack may be followed by any of the forms of subacute or chronic rheumatism. Recurrences of acute rheumatism are exceedingly common, especially in the rheumatism of young people.

Subacute rheumatism represents a milder form of rheumatism. The constitutional and local symptoms are less intense, but the duration of the disease is longer than in the acute form, and the condition tends to become chronic.

Complications of Rheumatism.-1. Cardiac Affections. -The endocardium and the pericardium may be involved in mild as well as in severe attacks of rheumatism, and may even be inflamed without any involvement of the joints, as in the abarticular rheumatism of children. The liability to heart-complications is most common in children; this liability diminishes with increasing age. The heart-membranes are not usually involved after the first week, if absolute rest and a restricted diet be enforced.

(a) Pericarditis, which complicates from 10 to 20 per cent. of the cases, may occur alone or with endocarditis. The inflammation may be fibrinous, fibrino-serous, or purulent, and it is often associated with hyperpyrexia and delirium. The rheumatic pericarditis of children often runs an obscure The child grows pale and emaciated, and dies of exhaustion or of heart-failure without the development of either dropsy or dyspnoea.

course.

(b) Endocarditis is more commonly a rheumatic lesion than pericarditis, and it appears in a large percentage of both mild and severe cases. Endocarditis may even be the solitary manifestation of the abarticular rheumatism of children. The mitral valve is the one most frequently affected. Valvular disease may not lead to serious consequences, or slow changes may ensue, resulting in valvular thickening and retraction. In a few cases there occurs an added infection of micrococci, resulting in malignant endocarditis.