real nature of the malady. In one instance, a gentleman in whom the disease commenced in the ball of the great toe, and always presented the characteristic phenomena of true gout, whose blood was likewise proved to be loaded with uric acid, the attacks were always excited by easterly winds, and in no way connected with any appreciable disturbance of the stomach or bowels. The local application of cold, even getting the feet wet, will often prove sufficient to excite a fit in gouty persons; and among the lower classes this cause is frequently operative, though not accompanied with indulgence in alcoholic liquors. When cold acts as an exciting cause of gout, the effect is due in part to its arresting the secretion of the skin, and checking the escape of acid; at the same time it must be remembered that a chill to the surface is necessarily accompanied by congestion of the internal organs, leading to functional derangement; cold may also occasionally act by its direct depressing influence upon the nervous system. Extreme mental or bodily labour, or depression from any other cause, is prone in some patients to induce a fit of gout. Sitting up late at night, especially when combined with severe study, will often occasion an attack. Van Swieten relates the case of an eminent mathematician, who brought on a fit by the long and constant application of his mind to the solution of a difficult problem; and Sydenham, as before noticed, always induced gout when devoting more than usual attention to the composition of his Tract. Violent excitement, as an outburst of passion, will act in a similar manner. Great bodily fatigue, as a long walk, is sometimes followed by a fit, and the same may result from a severe blow, fall, or other injury; many examples are on record in which fractures of limbs, dislocations of joints, surgical operations, have been followed by an attack of the disease. Local injury not only acts in exciting gout, but frequently determines the situation or locality of the inflammation ; thus, an injury to the knee or ankle will usually cause these joints to be primarily affected, although the great toe or some other part may subsequently become implicated. Hemorrhage may act as the exciting cause, and the effect is then probably due to depression. I have seen, for example, a first fit of gout produced by copious hematemesis; by loss of blood following the extraction of a tooth, by epistaxis and other forms of hemorrhage. On the other hand, it is not uncommon to find the suppression of an ordinary discharge of blood, as the sudden stoppage of the catamenia, immediately followed by a paroxysm. M. Duringe relates the case of a lady in whom the cessation of the catamenia, caused by a violent fright, was followed by several attacks of gout, which ceased when the patient again became regular. Cases illustrative of the effects of the suppression of an habitual hemorrhoidal discharge are by no means uncommon. The depression of the system caused by any other exhaustive disease will occasionally excite a fit of gout, and several instances arising from boils and carbuncles have come under my notice. In concluding this branch of our subject I may remark, it would appear that all causes leading either to an increased formation of acidity in the system, or its defective elimination by the skin, and all causes suddenly depressing nervous energy, have a powerful influence in exciting an attack of gout in subjects already predisposed to it. CHAPTER IX. PATHOLOGY OR NATURE OF GOUT: EVIDENCE OF A CLOSE RELATION BETWEEN GOUT AND URIC ACID-CHARACTERS AND COMPOSITION OF -CULLEN'S OBJECTIONS ΤΟ THE DOCTRINE OF THE HUMORAL GOUT-EXPLANATION OF THE GOUTY DIATHESIS AND PREMONITORY SYMPTOMS-EXPLANATION HAVING passed in review the phenomena ordinarily presented by gouty subjects, at least by those labouring under the more typical forms of the disease; having also ascertained the peculiar alteration of the blood and urine, and the morbid changes exhibited by the different tissues affected by gouty inflammation; and lastly, having studied the causes which act most powerfully both in predisposing and exciting the malady, we must now enter upon a very difficult investigation, the determination of the true nature or essence of gout. From a perusal of the contents of the preceding chapters, more especially such as relate to the altered composition of the blood, and the chemical characters of the external deposits occurring in gouty patients, and of the matter infiltrated in the tissues in and around the joints, the reader cannot fail to have remarked, whatever may have been his previous views of the pathology of the affection, that a very intimate relation exists between uric acid and the disease in question; such being the case, it will be advantageous to give a slight sketch of the nature and composition of this acid, and its relation to the organism in the different classes of animals, and under the varying circumstances of health and disease. Uric acid, or lithic acid, as it is sometimes called, occurs, when perfectly pure, in small white glistening plates, consisting of flattened rhombic crystals, so fine as to give it the appearance, to the naked eye, of an amorphous powder; but when examined by the microscope, its crystalline structure is at once recognised, and the forms it assumes are depicted in Plate 5, fig. 5, and Plate 6, fig. 1. When separated from the urine of serpents and birds, it is quite white; but when procured from human urine, it has usually a yellowish or red tint, depending on the great affinity possessed by this acid for colouring matters, and its power of carrying them down when precipitated from any coloured fluid. The solubility of uric acid * Uric acid was first discovered in urinary calculi and urine by Scheele in 1776; it was called lithic acid by Morveau, but afterwards named uric acid by Foureroy, by which designation it is commonly known at the present day. |