no SCIENTIFIC FEEDING OF ANIMALS 



work by mounting stairs, the proportion was from 

 28-1-36-6%-- an average of 33 ,:i: %- In experi- 

 ments with dogs doing draught work the percentage 

 of energy utilised was 28-8, and when the dog was 

 ascending and so performing work, it rose to 307%. 

 In eighteen experiments with a horse, it was found 

 that when turning a capstan at a walk the percentage 

 was 29-38%. As it is known that from a steam 

 engine of the best construction it is only possible 

 to get 15 % of the energy of the steam in the form 

 of utilisable work, it is easy to see how perfectly the 

 animal organism utilises the energy which is brought 

 to it. It must not be forgotten that the work that 

 any animal does in the ordinary sense of the word 

 is not the total energy that is obtained from the 

 nutrients. Another portion is utilised for the per- 

 formance of the internal work of the body — in- 

 creased activity of the muscles of the heart, organs 

 of respiration, etc. When the amount of energy 

 used in living muscle which has been cut from the 

 body is determined, it is found that half goes to 

 perform real work, whilst the other half takes the 

 form of heat. 



From one gram of pure isolated nutrient rumi- 

 nants obtain after deduction of all losses the follow- 

 ing amounts of energy — from carbohydrates 37-6, 

 from fat 8-57, and from protein 4-63 Cal. As only 

 one-third of this energy is available for muscular 

 work, one grm. of pure carbohydrate will yield 



