average, and destructive assimilation consequently very feeble, and the kidneys being called on to atone, as far as they are able, for the imperfect decarbonizing power of the lungs, render that assistance by the excretion of uric acid-a substance more rich in carbon than urea; for we find that in this condition of lung, uric acid exists in the ratio of one to seven, nearly five times its normal proportions.

The next disease on Becquerel's table is phthisis three days before death, and here we find, when oxidation is going on with intense rapidity and all the tissues of the body being burnt up under its all-devouring influence, that the quantity of uric acid excreted during the twenty-four hours is 9.8 grains, and that of urea 29.4, the ratio of uric acid to urea being one to three, uric acid being in excess ten times above the standard of health: but the increase in uric acid is not merely comparative but absolute; nearly a fourth more being excreted than in health, while only one-ninth the quantity of urea is eliminated. These results would at the first glance appear to be entirely subversive of Liebig's theory, but if we examine more closely into the reason why this occurs, it will, I think, both tend to show that we do not allow sufficient latitude to Liebig's views, and it will also tend to show that uric acid

is sometimes a secondary product; or in other words that the nascent urea, meeting in the circulation with carbonaceous impurities, the products of excessive oxidation, which are unable to escape from the circulation by the ordinary emunctories, becomes reconverted into uric acid, and by the compensatory action thus set up, the kidneys assist the incapacitated lungs and the overworked skin and liver in getting rid of the carbonaceous products of excessive oxidation. This opinion is confirmed when we look at the relative chemical composition of uric acid and urea.

It will be seen that the chief chemical difference in the composition of these two bodies consists principally in the very much larger quantity of carbon contained in uric acid than in urea, and we thus see how perfect oxidation will tend to diminish one and increase the other. Now, if the kidneys can take on compensatory action for the lungs and skin, as we know they often do in the elimination of aqueous excretion, why should not the same assistance be extended to the carbonaceous constituents of those excretions? I believe it is so extended, and that uric acid is the shape in which the kidneys give that assistance to

the great decarbonizing organs, when their functions are impaired, and when they have to take on compensatory action to atone for their deficiencies. We must now revert to Becquerel's list, to show how this excess of uric acid takes place in the urine during the last stages of phthisis.

When the ulcerative stage of phthisis has fairly set in, and the protective influence of the mucous membrane is thus lost, oxidation goes on with intense rapidity, a considerable portion of the lung tissue has been lost, and the remainder is unequal to the task of eliminating all the carbonaceous elements resulting from this excessive oxidation. Notwithstanding the profuse perspiration that is set up to assist the lungs, we find the venous blood still loaded with carbon, as shown by the profuse bilious diarrhoea set up, and the great hydro-carbonaceous reserves stored up in the liver from excess of materials sent to it for the elimination of bile, which the overtasked organ is unable to convert into its normal excretion, and which, as a dernier ressort, deposits itself in the shape of fat; and hence the curious and extensive deposit of that substance in this organ, while every other is undergoing rapid emaciation, and which we are in the habit of recognising as a common postmortem appearance in the fatty liver of phthisis.

But, notwithstanding the profuse colliquative perspiration and diarrhoea, and the fatty deposits in the liver, the blood is still loaded with carbon-the product of excessive oxidation, and which the disintegrated lung tissue, notwithstanding the active aid of the skin and liver, is unable to throw off-the kidneys are called on as a last and never-failing friend-a portion of the carbonaceous products of excessive oxidation reconverts the nascent urea into uric acid, and hence the appearance of that substance in the urine in the ratio of ten times its normal proportion, as compared with urea. The next disease on Becquerel's table is morbus cardis, with icterus: now morbus cardis is a somewhat vague term; but from the fact of its being accompanied by jaundice, we may assume that it is a valvular disease, and that the jaundice is merely one among many symptoms of distal venous congestion; and we here find that the ratio of uric acid to urea is 1 to 7.6-uric acid, as compared to urea, being in excess in the ratio of 4 times its proper proportion. The process of decarbonization is here again interfered with, partly by venous congestion, as well as by the sedative effect of retained bile. The next disease is acute hepatitis with icterus, in which the ratio of uric acid to urea is as 1 to 5.6, the uric

acid being in excess of the standard of health in the proportion of 6 to 1: but here again decarbonization is defective, not merely from the presence of retained bile, but the breathing is in a great measure thoracic, for the patient dreads the pressure of the diaphragm on the inflamed organ, and uses his abdominal muscles as little as possible for the purposes of respiration. The next disease is icterus: here the ratio of uric acid to urea is 1 to 16.1, being about double the quantity of uric acid, compared to urea, that is found in healthy urine, but relatively one-third less than exists in acute hepatitis with jaundice, and one-half less than is found in heart disease with jaundice. The comparative quantities of uric acid and urea in these three last diseases show in a remarkable manner that retained bile alone, although doubling the normal quantity of uric acid, is not nearly so influential in this respect as when retained bile is combined with other maladies which interfere with the due decarbonization of the blood during the functions of circulation and respiration. In milk fever, the last disease in Becquerel's list, the ratio of uric acid to urea is 1 to 7.47, rather more than four times the normal proportion. The defective action of the skin in this, as during the hot stage of all fevers,