6 THE CHEMISTRY OF CATTLE FEEDING 



a given quantity of another. Briefly, practical experience 

 does not, by itself, enable the farmer to exercise adequate 

 control over his operations, to deal successfully with abnormal 

 conditions which arise from time to time, or to understand 

 and utilise to the best advantage the advice of experts in 

 regard to such matters. To do this he must have exact know- 

 ledge of the requirements of the animals and of the composition 

 and properties as well as of the prices of the various kinds of 

 feeding stuffs. 



Such knowledge implies a clear understanding of the 

 relationships of the several classes of compounds which enter 

 into the composition of plants and animals, of the more 

 important processes of animal nutrition and of the nature of 

 the chemical changes involved. These subjects are discussed 

 in the first and second parts respectively of this book. The 

 third section is devoted to an account of the origin, composi- 

 tion and properties of the various kinds of food stuffs and 

 shows how they can be suitably combined, qualitatively and 

 quantitatively, for various purposes. 



The fourth section of the work is devoted to the chemistry 

 of dairying. This subject is closely connected with those of 

 the preceding sections and cannot, advantageously, be treated 

 apart from them. 



