62 THE NUTRITIVE VALUE OF DIFFERENT OIL-CAKES, 



nutrition. The time did not permit of my offering illustrations, 

 showing the applicability of the principles then mentioned, as it 

 respects the feeding and fattening of stock. Very cursorily 

 only I could allude to the nutritive qualities of a few articles of 

 food ; and I propose now, in continuation of my last year's lec- 

 ture, to enter more fully into detail, and to afford to you, by 

 illustration which I hope to bring before you, additional evi- 

 dence as to how necessary it is that the practical man should not 

 remain content with mere general knowledge, but become 

 acquainted with special knowledge acquired for practical pur- 

 poses. It is all very well for men of education to be generally 

 acquainted with some of the leading principles of nutrition of 

 the circumstances on which the nutritive value of food depends ; 

 but I am afraid such general knowledge will hardly assist the 

 farmer in rearing or fattening stock, for he requires for this 

 purpose special knowledge. He requires to understand the 

 special functions which the various constituents of food play in the 

 animal economy. Those of you who attended my last year's lec- 

 ture will remember that most articles of food contain the follow- 

 ing classes of substances : 



First. Flesh-forming materials, a class of constituents which 

 are required in the animal economy for keeping up the daily 

 waste of muscle, or for supplying new muscle. 



Secondly. Respiratory constituents and fat-forming materials 

 are always present in food ; and 



Thirdly. We have a class of substances which is applied in 

 the animal economy for the formation of bone materials. 



Now, it is upon the relative proportion of these materials that 

 the kind of food is more especially adapted for young animals, 

 for fattening stock, for milch cows, or for hard-working animals. 

 Thus, in a general way, food containing a considerable propor- 

 tion of ready-formed fat is beautifully adapted for the laying on 

 of fat, or for the keeping up of the respiration of animals, and 

 with it the animal heat ; whilst food rich in flesh-forming con- 

 stituents, rich in albumen, fibrine, gluten, and caseine, is particu- 

 larly well adapted for working animals, inasmuch as working 

 animals waste their muscle more rapidly than fattening animals. 

 Thus beans, peas, and leguminous seeds in general are particu- 

 larly well adapted for working horses, the reason being that in 

 this description of food a very considerable proportion of ready- 

 made flesh, so to speak, exists. 



In the subjoined diagram the proportion of gluten and water 

 in different articles of food is mentioned. 



