268 



Scientific Proceedings (129) 



127 (2087) 



An improved procedure for metabolism experiments. 

 By GEORGE R. COWGILL. 



[From the Sheffield Laboratory of Physiological Chemistry in Yale 

 University, New Haven, Connecticut.] 



The literature concerning metabolism contains many accounts 

 of failures of experiments due to refusal of the animals — 

 usually dogs — to eat the diets offered. 1 Investigations into the 

 physiology of vitamin-B as carried out at this laboratory have 

 shown this accessory food substance to be a factor essential for 

 the maintenance of the appetite. This fact is of peculiar interest 

 to students of metabolism. 



We are now able to give quantitative expression to this fact 

 in terms of the source of vitamin-B which we have tested, and 

 have utilized this relationship to make dogs eat during the 

 periods of metabolism experiments. 



A dog receiving a synthetic diet adequate in all respects ex- 

 cept vitamin-B, and containing only enough calories to maintain 

 a fairly constant body weight, requires for the maintenance of 

 appetite approximately 50 milligrams of "Yeast Vitamine (Har- 

 ris) Powder" per kilogram of body weight per day. Our pro- 

 cedure in metabolism experiments has been to weigh out the 

 daily doses, place them in gelatin capsules, and to give one cap- 

 sule to the animal each day. 



This method has been tested by workers at our laboratory 

 with entirely satisfactory results. Dogs have been maintained 

 on purely synthetic diets with remarkably constant daily output 

 of nitrogen over unusually long periods. 



Experiments designed to determine the minimum daily dose of 

 a wheat embryo preparation containing vitamin-B are now in 

 progress. 



i Many might be cited. More striking instances are: Forster, J., Zeitsch. 

 f. Biol, 1873, ix, 297; Steinitz, F., P finger's Archiv., 1898, lxxii, 75; Abder- 

 halden, E., and Oppler, B., Zeitschr. f. Physiol. Chcm., 1907, li, 226. 



