We may now consider whether these men, who had so greatly reduced the
extent of their proteid metabolism, and who had apparently attained a
condition of body equilibrium, were truly in nitrogenous equilibrium,
or free from any daily loss of nitrogen. To test this point, a careful
and exact comparison of the nitrogen intake and output was made for
a period of seven days, commencing on May 18. This was not easy to
accomplish, as the men were still allowed freedom in the quantity of
food eaten, and also in the choice of food, within the limits of the
menu provided, so that a large number of food analyses had to be made.
A greater difficulty, however, in obtaining proof of equilibrium lay in
the laudable ambition of the men to make a good showing,—for they had all
become interested in the main problem, and had acquired great faith in
the efficiency of a low proteid ration,—which led them to great caution
in the matter of eating during the balance trial, thereby running the
risk of diminishing in too great degree the fuel value of the food.
* * * * *
The following data obtained with Donahue are self-explanatory. The
figures showing the quantities of food at each meal are instructive, as
indicating the general makeup of the daily dietary, both as to quality
and quantity.