ANIMAL CALORIMETRY. 
THE INFLUENCE OF MECHANICAL WORK UPON PROTEIN 
ODIs DURING THE HEIGHT OF MEAT 
DIGESTION IN THE DOG. 
FOURTEENTH PAPER. 
By H. V. ATKINSON. 
(From the Physiological Laboratory, Cornell University Medical College, 
New York City.) 
(Received for publication, January 16, 1918.) 
In the last paper of this series! the heat production of a dog 
was measured, while he was running, during the 4th and 5th 
hours after the ingestion of 750 gm. of meat. As the dog would 
not retain urine during a period of exercise, it was necessary to 
assume, in making the calculations of the metabolism of the 
period, that the protein metabolism was the same as that which 
obtained in the same dog at rest after giving the same quantity 
of meat. However, this assumption might have been false 
because, on the one hand, the largely increased general blood 
flow might have furnished the gut with a notably increased 
volume of blood, thereby accelerating the absorption of amino- 
acids, or, on the other hand, one might conceive that the demands 
of the working muscles for blood might so decrease the supply 
of blood available for the intestines that a marked retardation in 
the absorption process might have ensued. 
A fox-terrier female weighing about 10.5 kilos was found to be 
willing to eat at most 600 gm. of meat daily at one meal, and 
upon this quantity the animal was maintained throughout the 
experiment. As it was found that the animal would not hold 
urine while running on the treadmill for a period of 1 hour, the 
period of active exercise was reduced to half an hour, though the 
urine was collected for the whole hour. 
A preliminary series of experiments showed that the maximal 
quantity of urinary nitrogen was eliminated during the 5th hour 
after administering meat, as appears in the following table. 
1 Anderson, R. J., and Lusk, G., Animal calorimetry, XIII, J. Biol. 
Cie. 191 tf XXxil, 421. 
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