7

       Since, however, some of the nitrogen of proteids is eliminated in forms other
than urea—as uric acid, xanthin, creatinin, etc.—even an exact determination.
of the urea is insufficient to provide an accurate measure of proteid katabolism.
We shall, therefore, for the present rest content with fixing the standard of
urea from the analyses shown in Table I and discuss the significance of the
results under the heading of the tota nitrogen.

        The smallest amounts of urea excreted occurred in the cases of one durwan
and of two domes; these were 5.56 grammes and 7.58 and 7.59 grammes
respectively for an average of five consecutive days' analyses. The maximum
quantities for similar periods were 19.68 in a durwan and 18.17 grammes in
(the average of) a student.

       The average excretion of urea on the whole series of 200 observations
works out to—students 12.95 grammes; durwans 12.97, and for domes and
mehtars 12.91 grammes in the 24 hours. (In the case of the last class the
averages hide the real facts; their output of urea varied very much from day to
day depending on their success or otherwise in obtaining a plentiful supply of
cheap proteid food.)

       A comparison of these standards of urea elimination with those for
Europeans shows a very marked difference—the amount of urea excreted by
the Bengali being less than half that usually accepted as the normal excretion
of the European.

       This important observation at once opened up the question of the bearing of the
metabolism of the Bengali on recent researches⁽¹⁾ on the problems of nutrition.⁽²⁾
Here we had ready-made the very conditions Chittenden had to plan and arrange
in order to carry out his brilliant series of investigations; and that, too, in a whole
community of millions of people accustomed to these conditions from early life.
From a clinical point of view also, a knowledge of this low standard of urea
excretion is a matter of practical importance in conditions requiring quanti-
tative analyses of the urine.

       4. The total Nitrogen. (Kjeldhal's method of estimation was adopted in
every instance.)

       In all problems concerning proteid metabolism in the body both as regards
its character and extent the quantitative study of the nitrogenous excretion is of
paramount importance.

       By the determination of the total nitrogen excreted in the urine we have a
measure of the total nitrogenous katabolism without regard to the specific
forms in which the waste products are eliminated. The nitrogen excreted in the

              ⁽¹⁾ Chittenden—Physiological Economy in Nutrition, 1905.
                                     The Nutrition of Man, 1907.

              ⁽²⁾ Leathes—Problems in Animal Metabolism, 1906.