COMPOSITION OF ANIMALS AND OF FEEDING STUFFS 6 1 



At the other extreme stand the figures reported by Trow- 

 bridge l for the composition of the kidney fat of a steer which 

 had received a submaintenance ration for about eleven months 

 and was in a very reduced condition : 



Water 81.42 per cent 



Protein 9.60 per cent 



Fat 4.59 per cent 



96. Glycogen storage. In addition to the large accumula- 

 tions of fat which the body sometimes contains, a much more 

 limited storage of reserve material may occur in the form of 

 the carbohydrate glycogen, especially in the muscles and in the 

 liver. 



Neumeister estimates that the liver of the average man may 

 store up approximately 150 grams of glycogen and the muscles 

 and other tissues approximately the same amount, making a 

 total of about 300 grams for the entire body. Estimating the 

 weight of the liver of a 1200 pound steer at 16 pounds and that 

 of the muscles at 800 pounds, and assuming a content of 10 per 

 cent of glycogen in the liver and one of 0.4 per cent in the mus- 

 cles, the total amount of glycogen contained in the body would 

 be approximately 2200 grams, but naturally this amount would 

 vary greatly at different times according to the conditions of 

 feeding and exercise. 



3. THE COMPOSITION OF THE ANIMAL AS A WHOLE 



97. Composition of entire body. In view of the great num- 

 ber of individual chemical compounds already discovered in 

 the animal body and of the lack of accurate quantitative methods 

 for the determination of many of them, any complete and de- 

 tailed estimate of the composition of the body as a whole is 

 manifestly impossible. The most that can be done is to de- 

 termine the proportions of the principal groups of compounds 

 enumerated in Chapter I. Several such investigations have 

 been made at different times. In all of them water and dry 

 matter, as well as the fat content of the latter, have been de- 

 termined, while sometimes determinations of the total nitrogen 



1 Proc. Amer. Soc. Animal Nutrition, 1910, p. 13. 



