NERVOUS SYSTEM.—In proportion as our knowledge of the intimate texture of ani mal and vegetable organisms advances, the doctrine gains ground that many of the phe nomena, called vital, are to be attributed to the special endowments of distinct forms of animal or vegetable matter ; distinct as regards their anatomical characters as well as their chemical composition ; distinct, therefore, as regards their physical properties; and, as ap pears not unreasonable to conclude, capable of inanifesting a distinct series of vital forces.
If great strength and power of resistance be requisite, a particular form of animal matter (gelatine) is united with an earthy material to constitute bone ; for the developement of strength, combined with elasticity or flexibility, this same kind of animal matter, or a modifi cation of it, is ag,ain employed, containing none or a very slight proportion of earthy ma terial, and forming the various kinds of cartilage and ligament; but for the play of the active powers of life--for the developement of living movements—whether in the performance of the nutritive functions, in growth and repro duction, or in the display of muscular force and activity, two substances, the most complex in chemical constitution of any in the body, and possessing the greatest atomic weight, are made use of to form the structures, on which these remarkable phenomena depend, namely, muscle and nerve. These structures are com
posed respectively of fibrine and albumen ; they are organized in analogous forms, and by their mutual reactions they exhibit the mar vellous effects which animal power is capable of producing.