406 STATE BOARD OF AGRICULTURE. 



j\CTUAL FOOD. 



Food is any substance by which all the functions and powers of the body 

 may be continuously supported — that by which an animal may live, grotv and 

 ii'orl\ The food of an animal must obviously be of the same composition as 

 the materials of the body, or be capable of transformation into substances of 

 identical composition ; for in this way only can it build up the animal system, 

 or repair its incessant Avaste. Again, only that portion of the food wliich is 

 digested affords value as food: the part which remains undigested, no matter 

 Avhat its composition, or how capable of sustaining life, fails utterly as food ; 

 it is cast out of the body in the excretions and may thus realize some profit as 

 manure, but it is wasted as food. 



By rejecting the imter, cellulose, and ash, found in the results or table of 

 analysis, we have left the materials which are capable of complete digestion in 

 the animal system, which are unquestionably of the highest value for animal 

 food. These are made up of two classes of substances; one containing only 

 carbon, hydrogen, and oxygen, and hence called carbohydrates ; the other con- 

 taining nitrogen in addition; this last class of substances is called albumitioids, 

 from tiie general resemblance to albumen or white of eggs. Since the muscles 

 of animals have almost identically the same composition as albumen, the albu- 

 minoids in food may be called the flesh-formers, while the carbohydrates, such 

 as starch, sugar, gum, and fat, may be called the force-formers. In the ani- 

 mal body we find both these classes of substances, the albuminoids as muscles 

 and tissues, and the carbohydrates chiefly as fat. A complete food therefore 

 requires the presence of both the albuminoids and tlie carbohydrates: an ani- 

 mal will starve when fed on only one of these classes for any long period. 

 You may say that a dog will live on meat for an indefinite time : but meat con- 

 tains layers of fat, and even lean meat is found to contain small globules of 

 fat scattered throughout its substance. If you will cut across the fibres of a 

 veiy dry piece of "dried-beef," and examine the cut surface you will see evi- 

 dence of the presence of fat. Kepeated experiments have shown that an 

 animal fed exclusively on pure albumen, or pure fibrin will starve just as cer- 

 tainly as when fed on pure sugar or fat. Boussingault of France fed a duc>i 

 on butter only, and although it was " as fat as butter," the duck starved to 

 death : the butter exuded from all parts of the body, and the feathers appeared 

 as if they had been soaked in melted butter, yet the duck died of starvation. 



In nature these two classes of substances are always found united ; the albu- 

 minoids are always associated witli some form of carbohydrates, and the carbo- 

 hydrates are always naturally associated with some form of albuminous matters. 

 We never find these substances in an entirely separate form, unless they have 

 been separated by some artificial process. 



KELATIVE VALUE OF ALBUMINOIDS AND CARBOHYDRATES 



Since an animal cannot be kept in a healthy condition without both albu- 

 minoids and carbohydrates, it is useless to ask which is the most valuable for 

 food, because the value is relative in both cases. It would be as sensible to ask 

 which is of most use in a watcii, tlie main-spring or the hair-spring. Any 

 watch-maker will tell vou that neither is valuable in a watch without the other ; 

 a watch will not go without the mainspring, and the same is true if the hair- 

 spring is gone. Each class of food will be valueless in the entire absence of the 

 other and in this sense they are of equal value. Yet they have very different uses 

 in tlie body ; the albuminoids serve to build and repair the waste of the muscular 



