136 DADD'S VETERINARY MEDICINE AND SURGERY 
tal natures. If, therefore, hard labor develops the function of 
either, rest, at suitalle intervals, preserves their integrity, and, 
therefore, must not be disregarded. 
In selectizzy: food for working animals, we must remember that 
they require certain inorganic equivalents, which seein tu be as 
necessary for the support of the system as nutriment. Sault, for 
example, is not nutritious; yet neither man nor brute can lung 
exist without it. Common salt, chloride of sodium, is deccm- 
posed in the stomach, and is there found in tke form of muriatic 
acid and sodx. 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 
xo that a horse must eat such rubbish as straw, potatoes, carrots, 
veets, and “stubble,” in order to supply the necessary material. 
Then consider that sulphur, iron, chlorine, lime, potassium, mag- 
aesium, and several other mineral substances, not in the ‘east 
nutritious, are alike necessary for the support and integrity of 
the living organism, and, therefore, should be the elements of 
foud. Some articles furnish the needful in abundance; in others 
there is a deficiency. This supplies another argument in favor 
ef 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 Ibs. of floui and 
wash it i water, frequently changing the same, you get 16 lbs. 
of gluten. This is the flesh-making principle, and represents 15 
Ibs. of the albumen of ficsh. 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 merely change the 
