It will be noticed that in the curve of female cases (indicated by the continuous line) there is an unbroken rise until the five-year period 45-49 is reached, and from that period onward an unbroken fall. When on the other hand we turn to the male eases we find no such regularity of the curve (denoted by the dotted line) and no definite maximum. No doubt the falling off in the number of • the female cases in later life is in part due to the smaller number of persons living; but this will not, I think, explain everything.
Influence of the Menopactse.—The period of maximum liability in women is seen to correspond approximately to the years following the period of the menopause, and common experience confirms the teaching of the statistics upon this point, for it is found that many cases originate within a few years of that period.
Eighteen patients of the series dated the onset of the disease from a period within two years before the menopause, and no less a num ber than 41 from the two years following that event. In 5 cases the onset was dated from the actual menopause. Adding these together we find that out of the 411 female patients, no less than 64 dated the com mencement of the malady from within two years of the climacteric.
Even in cases which date the onset from an earlier period of life the influence of the menopause is often conspicuous, for the disease is apt to acquire fresh vigor at that period, and to prove even more refractory to treatment than usual.
Exciting Causes.
Exposure.—There is a prevalent impression that exposure to cold and damp is among the most important of the exciting causes of multiple arthritis deformans, but I believe that the influence of these factors has been considerably exaggerated. Unquestionably those who suffer from it are extremely sensitive to changes in the weather, a fall of temperature or a spell of wet being frequently attended by a marked exacerbation of the articular pains, but even the patients themselves do not very often ascribe the commencement of their suf ferings to such causes, or at any rate not so often as might be expected if they were very potent etiological factors. In this respect arthritis deformans stands in conspicuous contrast to true rheumatism, for an attack of the latter disease is perhaps more often than not ascribed to getting wet through, sitting in damp clothes, sleeping in a damp bed, or such like causes.
There is a tendency at the present day to discredit the influence of cold and damp as provoking causes of many diseases in which their in fluence was formerly unquestioned, such as pneumonia, acute nephri tis, and other maladies; but however difficult it may be to reconcile their action with the teaching of modern pathology, the fact remains that the diseases in question frequently follow closely upon a definite exposure or chill,. and it seems more scientific to attempt to adapt our
theories to facts that rest upon such abundant evidence, than to re ject observations which do not at first sight fit in with our theories.
Although it is not improbable that in the case of arthritis defor mans the confusion of this malady with true rheumatism is largely responsible for the widespread opinion that it often dates from ex posure, it is impossible to deny that in some cases these factors do really seem to play the chief part in this causation, and when this is the case the exposure has generally been prolonged. Living in a damp house or in a cold and clamp neighborhood appear to be more potent than any sudden chill.
In only nine out of the five hundred cases was there a clear history of such an origin.
Dietetic Er rors.—Dietetie causes do not appear to have any im portant share in the causation of arthritis deformaus, that is to say, those which tend to excess; but scanty food or such as is not readily assimilated, by leading to malnutrition, certainly favors the develop ment of the disease. In this respect the disease in question stands in conspicuous contrast to gout, and a dietary which would be suited to a gouty patient may prove, and often has proved, very detrimental to one suffering from arthritis deformans.
Indeed any condition which tends to lower vitality appears to have a decided influence in favoring the development of the arthritis, and of the few children who suffer from it a considerable proportion come from very poor homes.
Acute illnesses of various kinds must be included among the excit ing causes and especially such as are apt to leave behind them a last ing impairment of the general health. Influenza possesses this qual ity in an eminent degree, and no one who has paid attention to the subject can fail to have been struck by the frequency with which patients who have developed arthritis deformans during the past few years date the commencement of their troubles from an attack of in fluenza acquired during the recent epidemic outbreaks of that malady. At the same time we must not forget that, owing to the enormous prevalence of influenza during those epidemics, the relation may be more apparent than real, and there is moreover a widespread tendency to ascribe almost all ailments to that cause. Of the occurrence of arthritis deformans as a sequel of acute rheumatism, as well of other diseases which tend to implicate the joints, I propose to speak at some length in a later section of this article.