SELECTION OF FOOD. 65 



the body, in which process carbon is used up, as 24 Ibs. of starch 

 or sugar. Thus any food that contains 10 per cent of fat is of equal 

 value to another which contains 24 per cent of starch. On ref- 

 erence to the table it will be found that corn contains 68.8 per 

 cent of fat formers, while cotton-seed-cake contains only 33 per 

 cent. But corn contains 5 per cent of fat, and cotton-seed-cake 

 16 per cent. The relative values of the two substances will 

 therefore be as follows: 



Starch, Fat, \ Equivalent Total 



Sugar, etc. or > to Starch. Fat-formers. 



Cora... 63.8 5.0 or 12.0 75.8 



Cotton-seed-meal 17.5 16. or 38.4 55.9 



If the quantities of flesh-forming elements of each are added to 

 the above totals, ft will be seen that cotton-seed-cake having four 

 times as much flesh- formers as corn, is the cheaper food of the 

 two. Again, whole flax-seed contains 55 per cent of fat-form- 

 ing elements, but as 37 per cent of these consists of oil, which is 

 equivalent to 88.8 per cent of starch, the total fat-forming power 

 of flax-seed is therefore equal relatively to 106.8 per cent in pure 

 starch. Cotton-seed free from the husk, and flax-seed, are there- 

 fore the most nutritive articles of feed for fattening. It is worth 

 while here to call attention to the high value of the peanut after 

 the oil is expressed, as food for stock animals we possess. As a' 

 substitute for oil-cake-meal where it cannot be procured conve- 

 niently, the following mixture has been suggested, viz : 



Ground Linseed 40 Ibs. 



Wheat Bran 60 " 



Flour ol Bone. 4 " 104 Ibs. 



The constituents of which per 100 Ibs. are : 



Flesh-formers, (albumen) 27 Ibs. 



Fat-formers, (fat 11 pei cent) 51 " 



Ash or Saline Matter 7 " 



Water 15 " 100 Ibs. 



This makes a most valuable combination of feeding substances for 

 a young growing animal, or a ewe giving milk. The greater nu- 

 tritive value of fat is explained by physiologists from the fact that 

 it is directly digested and assimilated, and enters into the circula- 

 tion and nutrition of the animal without change, except a very 

 fine mechanical division of its particles. On the other hand, starch 

 and sugar undergo a series of chemical transformations in the 

 course of which much of their volume and effect are expended. 



In choosing a variety of food then, for a special object, as for 

 instance the feeding of a young growing animal ; or the fattening 

 pf a mature animal and the sustenance of a sheep that produces a 



