Acute articular rheumatism is a general non-contagious, febrile affection, attended with multiple inflammations, pre-eminently of the large joints and very frequently of the heart, but also of many other organs; these inflammations observing no order in their invasion, succession, or localization, but when affecting the articulations tending to be temporary, erratic, and non-suppurating; when involving the internal organs proving more abiding, and often producing suppuration in serous membranes. It is probably connected with a diathesis—the arthritic—which may be inherited or acquired. It may present such modifications of its ordinary characters as to justify being called (2d) subacute articular rheumatism, and it may sometimes pass into the (3d) chronic form.

ETIOLOGY.—There is a general consensus of opinion that acute articular rheumatism belongs especially to temperate climates, and that it is exceedingly rare in polar regions; but respecting its prevalence in the tropics contradictory statements are made. Saint-Vel declares that it is not a disease of hot climates; Rufz de Levison saw only four cases of acute articular rheumatism, and not one of chorea, in Martinique during twenty years' practice; while Pruner Bey says it is common in Egypt, and Webb remarks the same for the East Indies. Even in temperate climates, like those of the Isle of Wight, Guernsey, Cornwall, some parts of Belgium (Hirsch), the disease is very rare—a circumstance not to be satisfactorily explained at present.

Acute articular rheumatism is never absent; it occurs at all seasons of the year, although subject to moderate variations depending mainly upon atmospheric conditions. It is the general opinion that it prevails most during the cold and variable months of spring, but this is not true of every place, nor invariably of the same place. Indeed, Besnier,1 after a long and special observation of the disease in Paris, concludes that there it is most frequent in summer and in spring. In Montreal, during ten years, the largest number of cases of acute rheumatism admitted to the General Hospital obtained in the spring months (March to June inclusive), when they averaged 51 a month; 33 was the average for all the other months, except October and November, when 26½ was the average. The statistics of Copenhagen, Berlin, and Zurich show a minimum prevalence in summer or in summer and autumn.

1 Dictionnaire Encyclopédique des Sciences Méd., Troisième Serie, t. iv.

Occupations involving muscular fatigue or exposure to sudden and extreme changes of temperature, especially during active bodily exertion, predispose to acute articular rheumatism; hence its frequency amongst cooks, maid-servants, washerwomen, smiths, coachmen, bakers, soldiers, sailors, and laborers generally.

While no age is exempt from acute articular rheumatism, it is, par excellence, an affection of early adult life, the largest number of cases occurring between fifteen and twenty-five years of age, and the next probably between twenty-five and thirty-five. A marked decline in its frequency takes place after the age of thirty-five, and a still greater after forty-five. It is not uncommon in children between five and ten, and especially between ten and fifteen, but is very rare under five, although now and then one meets with an example of the disease in children three or four years of age. While the acute articular affections observed in sucklings are, as a general rule, either syphilitic or pyæmic, some authentic instances of rheumatic polyarthritis are recorded. Kauchfuss's two cases among 15,000 infants at the breast, Widerhofer's case, only twenty-three days old, Stager's, four weeks old, and others, are cited by Senator.2

2 Ziemssen's Cyclop. of Pract. Med., xvi. 17.

An analysis of 4908 cases of acute rheumatism admitted to St. Bartholomew's Hospital, London,3 during fifteen years, and of 456 treated in the Montreal General Hospital during ten years,4 gives the following percentages at given periods of life:

London. Montreal.
Under 10 years 1.79 per cent.
From 10 to 15 years 8.1 per cent. Under 15 years 4.38 per cent.
From 15 to 25 years 41.8 per cent. From 15 to 25 years 48.68 per cent.
From 25 to 35 years 24.5 per cent. From 25 to 35 years 25.87 per cent.
From 35 to 45 years 14.2 per cent. From 35 to 45 years 13.6 per cent.
Above 45 years 9.5 per cent. Above 45 years 7.4 per cent.

The close correspondence existing in the two tables for all the periods of life above fifteen is very striking: the disparity between them below the age of fifteen may, I believe, be explained by the circumstance that the pauper population of Montreal is, when compared with that of London, relatively very small, and by the further fact that the practice of sending children into hospitals hardly obtains here.