Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: in the vegetable kingdom as potash itself; not a plant can be found from which phosphates are absent. Indeed it is easy to see the reason of this provision, if the important function fulfilled by one of the earthy phosphates in the animal economy be considered for a moment: it is phosphate ot lime which gives strength and stiffness to the bony framework of the animal body, and which salt must be furnished by the food the creature subsists upon. Taking into account, therefore, the fact that there is scarcely a green plant which does not furnish support to one or other of the vegetable feeders among the higher orders of the animal kingdom, it is easy to see the reason why of set purpose such a relation should have been established between the ultimate function and office of the plant—namely, the maintenance of sentient life, and a condition indispensable to the growth of the plant itself. Suffice it to say, as the result of exact experimental investigation, that without potash and phosphoric acid vegetable life cannot go on, much less nourish. Now let us inquire for a moment what sources of these two substances we possess in the solid earth itself; both are now, in the advanced state of analysis, easily discovered when sought for byappropriate means. We find, on making the investigation, that hardly a rocky bed can be examined without both coming to light—often mere traces, it is true, but still they are present . Here, however, a difficulty occurs, at least with one of them; with the exception of a very small group of the oldest sedimentary rocks, every stratum, almost without exception, from the tertiary formations to the ancient slate, contains embedded the remains of formerly existing races of animals. The shells and bones of those creatures contain phosphate of lime, which t...