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BOTANY All matter is composed of certain constituents (about seventy are at present known). Which, so far as the chemist is concerned, are indivisible, and are known as elements. Of the innumerable combinations of these elements, Ttwo general classes may be recognized,organic and inorganic bodies. While it is impossible, owing to the dependence of all organized matter upon inorganic matter, to give an absolute definition,we at once recognize the peculiarities of organic or living bodies as distinguished from inorganic or non-living ones. All living bodies feed, grow, and reproduce, these acts being the result of the action of forces resident within the organism. Inorganic bodies, on the other hand, remain, as a rule, unchanged so long as they are not acted upon by external forces. All living organisms are dependent for existence upon inorganic matter, and sooner or later return these elements to the sources whence they came. Thus, a plant extracts from the earth and air certain inorganic compounds which are converted by the activity of the plant into a part of its own substance, becoming thus incorporated into a living organism. After the plant dies, however, it undergoes decomposition, and the elements are returned again to the earth and atmosphere from which they were taken. Investigation has shown that living bodies contain comparatively few elements, But these are combined into extraordinarily complex compounds. The following elements appear to be essential to all ...


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