But it is not as an emunctory or purifier only that we must regard the skin; its influence and power have a wider range of action in the maintenance of health. Besides comprehending a vast system of drainage tubes, which open on the surface by seven millions of pores, and which in actual measurement would stretch over nearly thirty miles if laid end to end; besides this, which belongs to its purely emunctory function; besides, also, a wonderful and perpetual labour, by which the skin is drawing from the blood certain organic elements in the fluid state, and converting them into solid organic formations, which are known as cells and scales, these cells and scales being the tesselated mosaic with which the skin is finished upon the surface, so as to render it capable of existence in the atmosphere of the external world; besides this, and much more, unnecessary in this place to detail, the skin is converted into a kind of sponge by the myriads of bloodvessels which enter into its structure--bloodvessels, that many times in an hour bring the whole--ay, every drop--of the blood of the body to the surface; bring it that it may furnish the materials for the microscopic pavement; that it may be purified by the abstraction of its unwholesome principles; that it may breathe the vital air of the atmosphere without;--besides this, also, the skin near its surface is one vast network of nerves--nerves, mysterious organs, that belong in their nature to the unknown sources of the lightning, the electric currents of the universe. And, besides these again, there is every variety of animal tissue and contrivance by which all this apparatus is held together and maintained in the best state and position to ensure its safety and perfection. In truth, the contemplation of the structure and functions of the skin, when viewed with the eyes of the mind, is almost overwhelming; and as we gasp breathless, to gain an instant of reflection, the words of the Poet break upon our memory:-- "In human works, though labour'd on with pain, A thousand movements scarce one purpose gain; In God's, one single can its end produce, Yet serves to second, too, some other use."