is the cause of this increase in the proper quantity of uric acid as compared with urea; and the reason why is this:-during the hot stage of fevers the process of oxidation is excessive, but the elimination of the products of that oxidation is defective; the hot and dry skin of fevers is too commonly known to require even a passing remark; while the heart is stimulated to increased action, the capillaries seem to have lost their power, and that portion of the carbonic acid which should be carried off with the sebaceous fluid, is retained to form fresh combinations, and seek fresh means of exit from the circulation. We have now gone through Becquerel's tables, adduced by the late Dr. Bird for the purpose of disproving the correctness of Liebig's theory; but I think, by allowing that latitude to Liebig's views in certain diseases, which their peculiarities demand-a latitude not inconsistent with, but rendered essential by, the phenomena which occur in those diseases-we are able to account for the presence of uric acid in excess, not only when the various decarbonizing processes are imperfectly performed, but even when super-oxidation exists, as in fever and phthisis. And where the carbonized products of oxidation are generated so largely that the ordinary emunctories, the lungs, the liver, and

the skin, are unequal to their elimination as rapidly as they are formed, they are consequently retained in the circulation, and form fresh combinations. Hence uric acid; and hence the mode in which the kidney fraternizes with its brotherscavengers, the lungs, the skin, and the liver, in the purification of the highways and byways of our bodies from those nitro-carbonaceous impurities which have already served their purpose in the animal economy, and which, by their accumulation and retention in the circulation, would, were it not for the compensatory and vicarious action thus set up by the kidneys, be productive of derangement, disease, and death.

The practical conclusions to be drawn from the foregoing observations are, firstly, that uric acid and urea being derived from the action of oxygen on the albuminous textures of the body, and from such albuminous constituents of the

food as are imperfectly assimilated, or are in excess of what is required, it follows that whatever tends to check any of the great oxidizing processes, or leads to the accumulation in the circulation either of an excess of albuminous elements, or interferes with their due assimilation, will lead to the formation of an excess of uric acid, and a comparative deficiency of urea. Secondly, that the existence of excess of uric

acid sometimes occurs where metamorphosis of tissue is taking place with great rapidity, and the carbonized products of that oxidation, unable to escape, owing to impaired action of their ordinary emunctories, are retained, and form fresh combinations, by reconverting urea into uric acid. Thirdly, there appears to be grounds for believing that under rapid but imperfect oxidation of tissue the semi-metamorphosed elements of albuminous textures are occasionally carried into the circulation in an imperfectly oxidized state, as several stages must intervene between the nitrogenous tissues and their combinations with carbon, as they exist from the time they are first exposed to the action of oxygen as muscular tissue and their final elimination in the form of urea. The albumen of blood and the fibrin of flesh contain the largest quantity of carbon combined with nitrogen of all the animal compounds, and urea the smallest.

We thus see that the series of nitro-carbonaceous compounds in the body begin with albumen and end with urea. Albumen being the form in which nitrogen is combined with the largest amount of carbon, affords the greatest amount of pabulum for the inhaled oxygen, and in proportion as that process of oxidation is carried on in perfection, we have albuminous substances undergoing reduction into the lower compounds. From inosinic acid downwards, these compounds have no longer an organized form, but are crystallizable.

CHAPTER II.

Cold and moisture check oxidation of tissue, and thus generate uric acid-Reasons for supposing rheumatism a blood diseaseReasons for supposing the urate of soda the materies morbiEnfeebled condition of fibrous tissues essential for the development of the disease-Cold and moisture much more favourable to the induction of rheumatism than cold alone-All debilitating circumstances predispose-Effects of cold most severely felt while in a state of exhaustion-Although the symptoms vary in intensity in every case, they are sufficiently uniform to show their dependence on the existence of same causes-Dr. Taylor's observations, showing the relative frequency of fatal pericarditis in Bright's disease and acute rheumatism.

IN rheumatism, owing to the influence which cold and moisture exercise in checking oxidation in the systemic capillaries, uric acid is not oxidized as it otherwise should be into urea. The formation of uric acid from cold and moisture is not necessarily followed by rheumatism. Where the application of cold is only slight, but a moderate amount of uric acid is formed, which unites with the ammonia of the phosphate of soda and ammonia of the blood, and forms the urate of ammonia, which is seen as the red brickdust deposit of the urine of persons suffering from a common cold. When the checked action

C