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vegetable origin, consist of carbon, oxygen, and hydrogen,and, when burnt, they form carbonic acid and water.
278. When flesh or other animal matters are burnt,there remains a small quantity of inorganic ash, princi-pally salts of lime, magnesia, potash, and soda; someanimal substances, such as, for example, the blood, con-tain a small quantity of oxide of iron.
279. The bones of animals contain a very large pro-portion of earthy matters ; and, indeed, derive theirstrength and solidity principally from the quantity ofthose substances which they contain. When hones areburnt, there remains, after the combustion of all theorganic matter which they contain, about three quartersof their weight of earthy substances; these are princi-pally carbonate and phosphate of lime; bones consistof phosphate and carbonate of lime, cemented together,as it were, with gelatin and a little albumen; they alsocontain a small portion of oil. Ivory and the teeth ofanimals are composed of the same substances as bone.Hoofs and horn likewise contain phosphate and carbo-nate of lime, but in far less quantity; they consist prin-cipally of gelatin (276).
280. The same remarkable similarity of chemicalcomposition which is found amongst vegetable sub-stances is likewise observed amongst those of animalorigin; the various substances which constitute thebodies of animals, are, for the most part, almost iden-tical in composition, and, like vegetable substances,they appear more or less convertible into each other.