284 MANUAL OF AGFJCULTURE. 



It is obvious that a barely sufficient supply of food for the 

 daily wear and tear of an animal's existence will not contribute 

 to any increase of the animal's weight. To produce this last effect 

 an excess of nutriment over what is requisite for daily wants, 

 and even above the limits of the power of absorption and assimi- 

 lation, must be afforded. Albuminous bodies, as we have seen, re- 

 place and increase muscular tissue, whilst the oleaginous bodies do 

 the same for the fatty tissues. As the latter multiply, they become 

 deposited in all parts of the otherwise dense muscular tissues 

 of the body, increasing their bulk and juiciness, and rendering 

 them more tender and palatable and easy of digestion as human 

 food. The saccharine and amylaceous bodies are primarily appro- 

 priated for the respiratory processes ; but their excess, present in 

 the blood, is also capable of conversion into fat-forming material, 

 though in a less deGjree than the oleacrinous constituents. For 

 whilst 1 lb. weight of the latter can supply 1 lb. of fat to the 

 animal body, it takes 2i- lbs. of respiratory compounds to pro- 

 duce an equivalent result. To many it is probably an unsuspected 

 fact, that even in lean animals, the fat contained in the whole 

 body exceeds the quantity of albuminous substance. The follow- 

 ing: table, also derived from the last-named authoritv, and based 

 upon calculations resting upon the elaborate experiments of 

 Messrs Gilbert and Lawes, shows approximately the general 

 composition of the entire carcass of a lean and a fat animal 

 respectively : — 



Lean, Fat. 

 Mineral matters, . . .5 3 



Nitrogenous compounds, . . 15 12*5 



Fat, 24 33 



Water, ..... 56 48*5 



And the following, from the like authority, gives the percentage 

 composition of the increase in fattening oxen, sheep, and pigs : — 



Miueral Nitrogenous 



matter, compounds. Fat. Water. 



Oxen, . . 1-47 7-69 66-2 24-6 



Sheep, . . 2-34 7-13 70*4 20-1 



Pigs, . . 0-06 6-44 71-5 22-0 



Whence it appears that for every 1 lb. of albuminous matter 

 assimilated by the system, there are likewise assimilated, in 

 round numbers, 10 lbs. of fat and 3 lbs. of water. Theoretically, 

 it might be assumed that a similar proportion should prevail in 

 the food material given to fattening animals. P)ut this is not 

 sustained in practice. For the substances demonstrated by 

 experience as being the most efficient for fattening our stock — 

 for example, the various oil- cakes, grasses, leguminous plants, 

 turnips, &:c., all contain these proximate constituents in a much 



