174 THE CHEMISTRY OF THE FARM 



the rations of growing animals deduced from German 

 experiments. In this table only one-half of the 

 digestible fibre has been reckoned by the German 

 authors as available food, but the whole of the digestible 

 fibre is included in calculating the ratio of nitrogenous 

 to non-nitrogenous matter. 



It is very important that the food supplied to grow- 

 ing animals should contain a sufficient amount of ash 

 constituents, and especially of lime; for remarks on 

 this subject see p. 136. 



The Adult Animal. — The food of an adult animal, 

 not gaining or losing in weight, is employed for the 

 renovation of the tissues, the formation of hair, wool, 

 horn, &c., and for the production of heat and mechanical 

 work by its combustion in the body. 



Production of Heat. — In the case of an animal at 

 rest, not gaining in weight, the final results of the 

 digested food will almost wholly appear as heat and 

 as excrementitious matters, which are the products or 

 residues of the process of combustion. The tempera- 

 ture of the body of the animals on the farm varies 

 from 100° — 104'' Fahr., the horse having the lowest 

 temperature and the sheep and pig the highest. The 

 heat produced in the animal is lost by radiation from 

 the surface of the body, much is also consumed in 

 vaporising the water which is exhaled through the 

 lungs and skin. 



The smaller is the animal the greater is the loss of 

 heat per unit of weight, ani consequently the more 

 liberal must be the supply of food. Kubner deter- 

 mined the quantity of heat given off per day by a 

 series of dogs of different weight; his results are 

 shown in the next table. 



