410 



NEW ENGLAND FARMER. 



Sept. 



Every 100 parts taken in, consist of— 

 Food, solid and liquid, containing in all 75 per cent, of 



water - - - . . - - 



O.x'ygen taken in by the lungs, - - . - 



And are given off as — 

 Water perspired by the lungs and skin, 

 Carbonic acid, do. do., - - - - - . 



Evacuations, solid and liquid, - - - 



Other losses, ..... 



74.4 

 25.6 



100 



34.8 



30.2 



S4.5 



0.5 



100 



In general the substances perspired are to the 

 evacuations as 2 to 1. 



Of course, in an estimate of this kind, it is im- 

 possible accui-ately to put down the several quan- 

 tities given ofl' in the form of hair, nails, surface, 

 skin — both of the outer and inner parts of the 

 body — &c., &c., all of which are constantly shed 

 or cut, and as constantly renewed. It is useful, 

 however, in showing generally the relation which 

 the oxygen inspired bears to the other food which 

 the stomach receives, and ihe proportion of the 

 ■work of excretion performed respectively by the 

 perspiring organs, ami by the organs of evacua- 

 tion. 



KIND OF FOOD REQUIRED BY AXl.MALS AS INDICATED 

 BY TUE CO.MFOSITION OF TUE BLOOD. 



A knowledge of the kind of food required by 

 animals may be gathered, as wo have seen, from the 

 composition of the several parts of the animal body, 

 and a study of the functions they perform. The 

 muscles must be sustained ; thereibre gluten, al- 

 bumen, &c. — often popularity called muscular 

 matter, must 1)e eaten. The fat of the body must 

 be renewed, and hence fat should be present in 

 the food. And, as much carbon escapes from the 

 lungs and skin, it seems natural, if not absolutely 

 necessary, that starch or sugar should be intro- 

 duced into the stomach with the view of supj^ly- 

 ing it. The mineral matter of the flesh, blood, 

 and bones, must in like manner be provided. 



Tiie study of the excretiolis indicates, besides, 

 the quantity of food of each kind which ought to 

 l)e consumed. The quantity of carbon evolved in 

 the form of carbonic acid, of nitrogen in the forms 

 of urea and uric acid, and of saline matters in the 

 urine and solid excretions of a healthy man, afford 

 a means of approximating vory nearly to the quan- 

 tity of each whicli a sufficient food ought to con- 

 tain ; but the excretions du not alone tell us in 

 what forms the carl)on, nitrogen, and saline mat- 

 ters are best suited to the wants of the animal. 



Ain examination of the blood gives us this lat 

 ter nformation very clearly. The blood consists 

 essentially, besides the water, of albumen, sugar, 

 fot, and saline matter. The main purpose or ob- 

 ject of the process of digestion is to form blood ; 

 for out of the blood are drawn the materials neces- 

 sary to the wants of the bones, and of the various 

 tissues and fluids of the body. Those forms of 

 vegetable or animal matter, therefore, must be 

 beat adapted for food, whicli most resemble the 

 ingredients of the blood which is to be produced 

 from them. These will give the digestive organs 

 least trouble, or will be most easily digested. Thus 

 we arrive again at the conclusion that a healthy, 

 nourishing, and easily digestible food ought to 

 contain_ gluten or albumen, sugar or starch — 

 ■which, in the stomach, readily changes into sugar 

 —fat either of animal or vegetable origin, and sa- 

 line or mineral matters of various kinds. Of 



course, if the stomach of the animal be in an un- 

 healthy condition, the quality of the foodmay re- 

 quire to be adapted to its unnatural condition ; 

 but this does not affect our general conclusion. 



IMPORTANCE OF A 31IXED FOOD. 



All these diffei'ent modes of examining the ques- 

 tion, therefore, indicate not only the advantage 

 but the necessity of a mixed food to the hcaltliy 

 sustenance of the animal body. Hence the value 

 of any vegetable production, considered as t\\Q sole 

 food of an animal, cannot be accurately deter- 

 mined by the amount it may contain of any ons 

 of those substances, all of which together are ne- 

 cessary to build up the growing body of the young 

 animal, and to repair the natural waste of such 

 as have attained to their fullest size. 



Hence the failure of the attempts that have been 

 made to support the lives of animals by feeding 

 them upon pure starch or sugar alone. These 

 substances would supply the carbon perspired by 

 the lungs and the skin ; but all the natural waste 

 of nitrogen, of saline matter, of earthy phosphates, 

 and probably also of fat, must have been with- 

 drawn from the existing solids and fluids of their 

 living bodies. The animals, ia consequence, pined 

 away, became meagre, and sooner or later died. 



So some have expressed surprise that animals 

 have refused to thrive — have ultimately died, when 

 fed upon animal jelly or gelatine alone, nourish- 

 ing though that substance, as -part of the food, 

 undoubtedly is. When given in sufficient quan- 

 tity, gelatine might indeed supply carbon enough 

 for respiration, with a great waste of nitrogen, but 

 it is deficient in tlie saline ingredients which a 

 naturally nourisliing food contains. 



Even on the natural mixture of starch and glu- 

 ten which exists in fine wheaten bread, dogs have 

 been unable to live beyond 50 days, though others 

 fed on household bread, containing a portion of 

 the bran — in which earthy matter more largely 

 resides — continued to thrive long after. It is im- 

 material whether the general c^uantity of the 

 ivhole food be reduced too low, or whether one of 

 its necessary ingredients only be too much dimin- 

 ished or entirely withdrawn. In either case the 

 eflect will be the same — the animal will become 

 weak, will dwindle away, and will sooner or later 

 die. 



The skill of the feeder may often be applied with 

 important economical effects to the proper selec- 

 tion and mixture of the food he gives his animals 

 generally, and at various stages of their growth. 



It has been found by experiment, for example, 

 that food which when given alone, does not fat- 

 ten, acquires that property in a high degree when 

 mixed with some fatty substance, and that those 

 which are the richest in the muscle-forming in- 

 gredients produce a comparatively small effect, un- 

 less they contain also, or are mixed with, a con- 

 siderable pro^iortion of fixtty matter. Hence the 

 reason why a stone of linseed has been found by 

 some to go as far as two stones of linseed cake, and 

 why the Rutlandshire farmers find a sprinkling of 

 linseed oil upon the hay to be a cheap, wholesome, 

 and fattening addition to the food of their cattle 

 and horses. 



A Merino sheep of 55 lbs. contains about 20 lbs. 

 of fat, but four-fifths of any subsequent addition 

 consists of tallow, hence we may infer that oily 

 food should be profitable in fattening sheep. To 

 pigs the same remark applies ; and, in prac- 



