------------------+--------------+--------------+-------------- | | Uric acid. | Amount of Time. | Urea. Grams. | Milligrams. | urine. C.C. ------------------+--------------+--------------+-------------- 10-11 | 1·07 | 26 | 175 11-12 | 1·13 | 27 | 118 12-1 p.m. | 1·07 | 24 | 164 1-2 (meal). | 0·64 | 21 | 60 2-3 | 1·12 | 22 | 43 3-4 | 1·16 | 38 | 41 4-5 | 0·84 | 40 | 53 5-6 | 1·16 | 56 | 59 6-7 | 1·20 | 39 | 56 7-8 | 1·37 | 30 | 95 8-9 | 1·47 | 33 | 183 9-10 | 1·33 | 24 | 155 10-11 | 1·33 | 23 | 180 ------------------+--------------+--------------+-------------- It is clear from the results obtained that a very definite increase of endogenous purin excretion ensued, and that the said increase occurred sooner as regards _uric acid_ than urea. This bears out what Mares demonstrated many years ago, viz., that the greatest increase in uric acid excretion occurs in a few hours after a meal, whereas the increase in the case of urea comes more tardily, not reaching its maximum until some hours after. Horbaczewski referred such increase in uric acid excretion to a digestive _leucocytosis_; in other words, that the uric acid was the outcome of destruction of the leucocytes, and consequent formation of purin from the released nucleic acid. Unfortunately for this theory, the period of most marked augmentation in uric acid excretion ensues when the leucocytes are most in evidence in the blood-stream, not _after_ they have disappeared, as would be the case if uric acid was derived from the purin product of the nucleic acid liberated by leucocytic destruction. We have a parallel instance in the case of _pneumonia_, in which it has been shown that the elimination of uric acid and other purins is at its acme when the leucocytes are most abundant; in other words, the highest uric acid output coincides with the period of most marked leucocytosis, whereas during the post-critical stage, viz., when leucocytes are being destroyed in great numbers, the output of uric acid is very markedly lowered. Discussing Horbaczewski’s theory in light of the above criticisms, MacLeod suggests, “that the facts appear to indicate that the purin substance is a metabolic product of the living leucocytes,” and not, so to speak, the chemical outcast of their disruption and death.