52 SCIENTIFIC FEEDING OF ANIMALS 



1-2 days of hunger 975 gr. protein and — gr. fat. 

 3-8 „ „ ,, 670 „ „ io-o „ 

 9-*5 „ » » 5*92 „ „ 7*4 » 



16-18 „ „ „ 13-27 „ „ i-o „ 



It is the need of heat and energy which causes 

 the continued decomposition of tissues and which 

 ceases only with the death of the animal. All 

 the energy which is utilised for any form of work, 

 be it in a machine or in the animal body, is finally 

 converted into heat. The total heat, then, that an 

 animal gives off when starving can be regarded as 

 a reliable measure of the energy required for the 

 maintenance of life. 



The loss of heat which a body suffers in surround- 

 ings of a lower temperature depends upon the surface 

 of the warm body and not upon the weight. If two 

 pieces of metal of equal weight are taken, and one of 

 them made into a ball and the other beaten into a 

 thin sheet, then if both are heated to ioo° C. and 

 allowed to cool the sheet becomes cold more quickly 

 than the ball ; the larger surface radiates more heat 

 than the smaller. This law has often been shown to 

 hold good also for the living animal. An investiga- 

 tion on the energy metabolism of seven starving dogs 

 of different weights gave the following results — 



Body weight in kilograms : 31-2, 24-0, 19-8, 18-2, 

 9-6, 6-5, 3-2. 



Body surface in sq. centimetres : 10,750, 8805, 

 7500, 7662, 5286, 3724, 2423. 



