A Study of the Diet and Metabolism of Eskimos. 



43 



rest, marked *. If these are excluded according to the usual rules i 

 and if we exclude further the periods in which the resp. quotient of 

 the non protein metabolism has been above 1 and in which the pro- 

 duction of heat is rather uncertain, marked ) , we obtain, after reduc- 

 tion of the observed calories as before, the following series: 



N in urine 

 sr. 



Reduced 



metabolism 



Calories 



N in urine 

 gr. 



Reduced 



metabolism 



Calories 



Mean deviation of one \ +опа 

 determination / 



+ 42.8 



An increase in N excretion of 13.1 gr. corresponds therefore in 

 our experiments to an increase in metabolism of 28.4 + 16.4 Cal. or 

 2.16 + 1.25 Cal. per gr. N in the urine or 8.6 ^ 5.0 7o of the total 

 energy corresponding to 1 gr. N. This figure for the specific dynamic 

 action of nitrogen is remarkably low, and if we attempt a calculation 

 from the night values alone we find it lower still. We do not think 

 it advisable, however, to draw far reaching conclusions from the result. 

 It appears to be very natural for people who have been exclusively 

 carnivorous through untold generations and who possess the power 

 of retaining large amounts of protein for periods exceeding 24 hours 

 but it will have to be tested by laboratory experiments in which the 

 conditions can be better defined and enforced ^. 



' Davenport: Statistical Methods 2 ed., 1904, p. 12. 



2 When the printing of the present paper was practically completed a 

 series of very important papers by Lusk, Riche and Williams (Journ. of Biol. 

 Chem. Vol. XII to XIII) came to hand. These writers have, with a technique 

 far superior to ours, studied the metaboUsm in short consecutive periods in a 

 dog after much meat and also after the administration of individual amino 

 acids. They have demonstrated clearly a retention of carbon from protein in 

 the form of carbohydrate, and they find further that in the dog the ingestion 

 of meat or certain amino acids causes a very considerable rise in the total 

 metabolism by stimulating the catabolic activity of the organism. 



