In the seed-cell we find, by minute examination, the embryo of the future plant carefully preserved in its envelop of starch and gluten. The investigations which have been carried on upon the vitality of seeds appear to prove that, under favorable conditions, this life-germ may be maintained for centuries. Grains of wheat, which had been found in the hands of an Egyptian mummy, germinated and grew; these grains were produced, in all probability, more than three thousand years since; they had been placed, at her burial, in the hands of a priestess of Isis, and in the deep repose of the Egyptian catacomb were preserved to tell us, in the eighteenth century, the story of that wheat which Joseph sold to his brethren. The process of germination is essentially a chemical one. The seed is placed in the soil, excluded from the light, supplied with a due quantity of moisture, and maintained at a certain temperature, which must be above that at which water freezes; air must have free access to the seed, which if placed so deep in the soil as to prevent the permeation of the atmosphere never germinates. Under favorable circumstances, the life-quickening processes begin; the starch, which is a compound of carbon and oxygen, is converted into sugar by the absorption of another equivalent of oxygen from the air; and we have an evident proof of this change in the sweetness which most seeds acquire in the process, the most familiar example of which we have in the conversion of barley into malt. The sugar thus formed furnishes the food to the now living creation, which, in a short period, shoots its first leaves above the soil; and these, which rising from their dark chamber are white, quickly become green under the operations of light. In the process of germination a species of slow combustion takes place, and—as in the chemical processes of animal life and in those of active ignition—carbonic acid gas, composed of oxygen and charcoal, or carbon, is evolved. Thus, by a mystery which our science does not enable us to reach, the spark of life is kindled—life commences its work—the plant grows. The first conditions of vegetable growth are, therefore, singularly similar to those which are found to prevail in the animal economy. The leaf-bud is no sooner above the soil than a new set of conditions begin; the plant takes carbonic acid from the atmosphere, and having, in virtue of its vitality, by the agency of luminous power, decomposed this gas, it retains the carbon, and pours forth the oxygen to the air. This process is stated to be a function of vitality; but as this has been variously described by different authors, it is important to state with some minuteness what does really take place.