Early in January, the body-weight of the men having become practically
stationary and the proteid metabolism, as measured by the output of
metabolized nitrogen, having been reduced to a low level, an attempt
was made to see if the men were truly in a condition of nitrogenous
equilibrium. A six-day period was used, during which all the food for
each meal was carefully analyzed, the nitrogen in every sample of food
being determined in duplicate by the Kjeldahl-Gunning process. The fæces
of the period were separated by lampblack, given at appropriate times in
gelatin capsules, and all necessary precautions observed to insure an
accurate nitrogen balance. The accompanying tables of results give all
the necessary data.
The average nitrogen intake per day was 8.23 grams, and the average fuel
value of the food per day was 2078 calories. These are the figures for
Oakman. With some of the other men there were slight variations from
these figures, as shown in the tables—owing to slight variations in
diet. Without exception, all the men showed a minus balance, indicating
that on this diet the body was losing nitrogen. In other words, the diet
as a whole was insufficient for the needs of the body in every case.
Whether this was due to lack of sufficient proteid or to an insufficient
amount of fat and carbohydrate, _i. e._, a too low fuel value, cannot be
said definitely, but there is every reason to believe that the amount
of non-nitrogenous food was insufficient to furnish the requisite fuel
value, and consequently body proteid was drawn upon to supply the
deficiency. The loss of nitrogen to the body per day varied as a rule
from 0.5 to 2.0 grams. In one case only, viz., Broyles, was there a close
approach to a balance. In his case there was a minus balance of only 0.12
gram of nitrogen per day.
The average daily output of nitrogen through the urine for this six-days
period (Oakman’s case) was 7.52 grams.
[Illustration: FRITZ
_Photograph taken at the close of the experiment._]