INTERNAL WORK. 381 
Prorerps.—Proteids in the form of meat or a mixture of meat 
and flesh-meal, with in some cases small amounts of fat, caused a 
very marked and prompt increase in the metabolism of the dog. 
The maximum effect was usually reached about the third or fourth 
hour and continued with but slight diminution up to the seventh 
or eighth hour with small rations and as long as to the twelfth or 
fifteenth hour with large rations. As in the case of fat and carbo- 
hydrates, the increase was greater with large rations, but its amount 
largely exceeded that caused by either of the two former groups of 
nutrients, reaching in some cases 90 or more per cent. of the fasting 
value. 
The results were more irregular than in the preceding experi- 
ments, and were apparently influenced by a peculiar effect of the 
food upon the type of respiration. The author, however,* com- 
putes from three selected series of experiments the following 
approximate averages for the twenty-four hours: 
[Heat Production in 24 Hours. 
Proteids | ache 
No, of se is ue le 
Experiment. Grms. | of Food, | Fasting, | With fo 
Cals. Cals.” Food, (77> 
RO | ie, eae 
83 and 89...... 82.5 338 1030 1086 56 16.57 
102 “ 106...... 230.0 °943 963 1079 116 12.30 
95 “ 96...... 370.6 1520 1059 1303 244 16.05 
The amount of the proteid metabolism was not determined in 
these experiments, but the author points out that they were made 
on the first day of the feeding, and that it is probable that the 
proteid metabolism, and consequently the heat production, would 
have increased more or less had the feeding, particularly with 
excess of food, been continued longer. 
Bone, when fed in large quantities to the dog, was found to 
cause a greater increase in the metabolism than corresponded to the 
nitrogenous matter estimated to have been resorbed from it, and 
the difference is ascribed to the mechanical effect upon the digestive 
tract. 
* Loc. cit., p. 78. 
