136 DADD'S VETERINARY MEDICINE AND SURGERY 



fat natures. If, therefore, hard labor develops the function of 

 either, rest, at suital le intervals, preserves their integrity, and, 

 therefore, must not be disregarded. 



In selecting food for working animals, we must remember that 

 they require certain inorganic equivalents, which seem to be as 

 necessary for the support of the system as nutriment. Salt, for 

 example, is not nutritious; yet neither man nor brute can long 

 exist without it. Common salt, chloride of sodium, is deccrc- 

 posed in the stomach, and is there found in the form of muriatic 

 acid and soda. The former is supposed to aid digestion, and the 

 latter eliminates bile. Neither is phosphorus (found in straw) 

 nutritious, yet that article is absolutely necessary for the support 

 of animal life. It is an element of both vegetable and animal 

 organization. The former absorbs it from the soil, and, in turn ; 

 yield it to animals, by the process of digestion. Oats and beans 

 are nitrogenous compounds, flesh-making equivalents, yet they 

 furnish only one part in a thousand of the article we need — phos- 

 phorus; while cut straw, potatoes, and several other "inferior" 

 vegetables, contain more than double the quantity of the same ; 

 so that a horse must eat such rubbish as straw, potatoes, carrots, 

 beets, and "stubble," in order to supply the necessary material. 

 Then consider that sulphur, iron, chlorine, lime, potassium, mag- 

 nesium, and several other mineral substances, not in the least 

 nutritious, are alike necessary for the support and integrity of 

 the living organism, and, therefore, should be the elements of 

 food. Some articles furnish the needful in abundance ; in others 

 there is a deficiency. This supplies another argument in favor 

 of variations in diet. 



A lecturer on physiology has remarked that " there exists a 

 peculiar analogy between vegetable productions and living ani- 

 mals. Animal and vegetable fibrine — albumen of eggs and the 

 gluten of wheat — contain about 15 per cent, of nitrogen, so that 

 they are somewhat identical. If you take 100 lbs. of flou; and 

 wash it i ■ water, frequently changing the same, you get 15 lbs. 

 of gluten. This is the flesh-making principle, and represents 15 

 lbs. of the albumen of flesh. The gluten of flour, caseine of cheese 

 and peas, albumen of eggs, and the flesh of an animal contain 

 also a relative amount of carbon, hydrogen, and oxygen ; so that 

 the flesh of animals is already prepared for them in the vegeta- 

 ble world. The digestive organs of animals merelv change the 



