Other arguments which have been brought forward in support of the rheumatic theory are based upon the part played by cold and damp in the causation of the disease, and the association with the joint lesions of visceral and other affections similar to those met with in connection with true rheumatism. Both of these subjects have been already dealt with at some length, and it is only necessary to repeat here that I believe that the influence of cold and damp in the causation of arthritis deformans has had undue stress laid upon it; and that the endeavors to prove the occurrence in association with this disease of the abarticular lesions of rheumatism have resulted rather in the demonstration that arthritis deformans is not attended by any visceral lesions other than such as may be regarded as inter current disorders.
An exception should perhaps be made in favor of the subcutaneous rheumatic nodules, but, as was pointed out in speaking of these, our knowledge of the nodules themselves and of the nature of the joint lesions with which they are associated is not yet sufficiently complete to allow of any definite conclusion being drawn from their occurrence. It must, however, be admitted that at first sight the development, in association with apparently typical cases of arthritis deformans, of excrescences so strangely like those which have been regarded as pathognomonic of the true rheumatic process does supply a powerful argument in favor of the rheumatic theory.
The argument from the absence of visceral lesions loses some of its force from the fact that arthritis deformans is most apt to com mence at a period of life when true rheumatism loses much of its ten dency to attack the heart, and is apt to limit its activity to the joints alone; but the immunity from cardiac complications is quite as con spicuous in those cases in which arthritis deformans is developed in early adult life and even in childhood, if we exclude those instances in which it appears as a sequoia of acute rheumatism.
Those who regard arthritis deformans as a form of chronic rheu matism have to admit that the chronic joint lesions which follow upon the acute forms of that disease have more commonly a different character, that as a rule the destruction of cartilage and ten dency to the formation of bony outgrowths is wanting, fibrous auky losis and thickening of the joint capsules being the changes more usually observed. In such cases the superficial resemblance to ar thritis deformans in its early stages may be very close, but if, as is fortunately very seldom the case in the earlier stages of the affection, the case comes to a post-mortem examination, on cutting through the greatly thickened capsule the cartilages and articular ends of the bones are found intact.
While we are still ignorant of the nature of the materies morbi of acute rheumatism the question under discussion cannot be settled once and for all by an appeal to its constant presence or absence in cases of arthritis deformans ; and we must continue to rely solely upon circumstantial evidence for the solution of the problem. To me such evidence as is forthcoming in favor of the contention that this malady is a form of chronic rheumatism appears to be greatly outweighed by that which is opposed to this contention, and especially by the evi dence, presently to be discussed, which tells in favor of a quite differ ent origin.
The theory which regards arthritis deformans as a mixed disease resulting from the blending of rheumatism and gout, which is identi fied with the name, and supported by the great authority of Jonathan Hutchinson," is intimately mixed up with the hypothesis of the exis tence of an arthritic diathesis, which serves as a basis upon which rheumatism and gout and also articular disorders of other kinds may be developed.
Modern pathology has tended to drift away from the notion of such diatheses which held so prominent a place in the writings of French medical authors in the earlier part of the century. Possibly it may turn out that we have gone too far, and the pendulum may swing back again toward the older ideas. It is indeed probable that it will so swing back, to this extent at any rate, that more attention will be paid in the future than has lately been the case to the influ ence of the tendencies and peculiarities of the individual in modify ing the course and features of any disease to which he may fall a victim.
It must be acknowledged that the more one studies the diseases in question the more one is struck by the peculiar way in which they are sometimes associated in a family, and it is difficult to reconcile such instances with the obvious and conspicuous differences which they otherwise present, and with the evidence which points to the possession by each disease of an entirely distinct pathology, and to their inclusion in quite different groups of diseases. For example, the apparent liability of the daughters of gouty parents to arthritis deformans, to which reference was made earlier, lends support to Hutchinson's views; but on the other hand all that has been said against the rheumatic theory applies equally to this one, and we have the fact observed by Sir A. Garrod that no excess of uric acid is to be detected in the blood of patients suffering from arthritis defor mans, and the point upon which Sir Dyce Duckworth has laid stress, that arthritis deformans is common in countries in which true gout is practically unknown.