The above statements regarding the distribution of the eliminated nitrogen among the different end products refer to results obtained upon an ordinary mixed diet containing the usual amount of protein. Folin has shown by a careful and extended study of the urines of healthy men living first upon high and then upon low protein diets, that the distribution of the nitrogen between urea and the other nitrogenous end products depends very largely upon the absolute amount of nitrogen metabolized. In the case of a man who on one day consumed high protein diet free from meat, and a week later was living on a diet of starch and cream, which furnished in all about 6 grams of protein per day, the distribution of end products was changed as shown in the following table:

Thus, on passing from the high protein to the low protein diet (both being free from meat products) there was a marked decrease in both the absolute and the relative amounts of urea, and a decrease in the absolute, but increase in the relative, amount of uric acid, while the absolute amount of creatinine remained unchanged, so that its relative amount was greatly increased.