PHYSIOLOGY: ATKINSON AND LUSK 
247 
(meat, 100 grams; lard, 20 grams; and biscuit meal, 100 grams) remained 
persistently (even after 2| weeks) at a higher level than had obtained prior 
to the meat ingestion. This confirms F. G. Benedict's idea of a higher basal 
metabolism in the presence of 'surplus' cellular nitrogen, or the 'improvement 
quota' of protein according to Rubner's suggestive terminology. When meat 
was given after the partial depletion of the body cells of their 'improvement 
quota', protein was retained in greater measure, less protein was metabolized 
and the heat production was therefore lower than on a subsequent day (ex- 
periments 46, 47; 51, 54). 
The following table gives the method of calculation followed: 
Experiment 55. N in urine per hour = 1.58 grams 
grams grains 
N-CO2 14.77 N-O2 13.35 N-cals 41.89 
Resp. CO2 11.42 Resp. O2 10.42 Deposit cals 9.92 
Dif 3.35 2.93 Indirect cals 31.97 
Direct cals 31.98 
R. Q. of deposit = 0.83 
R. Q. per hour— 0.81, 0.74, 0.80, 0.84. R. Q. for whole period = 0.797 
In the above table: 
N-CO2 is the amount of CO2 derivable from the protein metabolism during 
an hour, 
N-O2 is the amount of O2 necessary to oxidize the protein metabolized in 
one hour. 
Resp. CO2 and Resp. O2 are the amounts of CO2 and O2 which were actually 
respired during an hour. 
The difference represents (1) the CO2 which would have been expired had 
all the retained carbon of the protein metaboHsm been oxidized and (2) the 
O2 which would have been employed in that process. The relation between 
the volumes of these two gases indicates that the material retained and un- 
oxidized would have yielded a respiratory quotient of 0.83, which indicates 
the retention of a pabulum, approximately half of the calories of which were 
derived from fat and half from glucose. 
N-cals. is the quantity of heat which would have been eliminated by the 
dog had all the protein metabolized by the dog been completely oxidized. 
From this is subtracted the number of calories estimated to have been re- 
tained as a mixture of fat and glucose aforesaid. The difference represents 
the calories as calculated by indirect calorimetry, which in this case agrees 
exactly with those directly measured by the calorimeter by the method of 
direct calorimetry. 
