Note 72 — Chapter III

Mr. George Rainey many years ago made us acquainted with the fact that certain of the appearances presented by the shell or other hard structures of animals, and which had hitherto been referred to as cell-development, are really governed by the physical laws which govern the aggregation of certain crystalline salts when exposed to the action of vegetable and animal substances in a state of solution. Mr. Rainey furnished a process for obtaining artificially a crystalline substance which shall so closely resemble shell structure that it can barely be distinguished from it. The chemical substances to be used in the preparation of the artificial shell, or calculi, are a soluble compound of lime and carbonate of potash or soda, dissolved in separate portions of water, and mixed with some viscid vegetable or animal substance, as gum or albumen, and mixing the several solutions together. The mechanical conditions required are that such a quantity of each of the viscid materials in each solution shall be of about the same density as that of the nascent carbonate of lime, and at perfect rest. This state of rest will require from two to three weeks or longer. Mr. Rainey shows the analogy or identity of his artificially formed crystals with those found in natural products both in animals and vegetables, chiefly confining himself to the structure and formation of shells and bone, pigmental and other cells, and the structure and development of the crystalline lenses, which he contends are all formed upon precisely the same physical principles as the artificial crystals.