System, are guided by physiological relations, latently in Botany, but conspicuously in Zoology. From the epoch of Cuvier's Règne Animal, the progress of Systematic Zoology is inseparably dependent on the progress of Comparative Anatomy. Hence I have placed Cuvier's Classification of animal forms in the next Book, which treats of Physiology.] Fearful and wondrous is the skill which moulds Our body's vital plan, And from the first dim hidden germ unfolds The perfect limbs of man. Who, who can pierce the secret? tell us how Something is drawn from naught, Life from the inert mass? Who, Lord! but thou, Whose hand the whole has wrought? Of this corporeal substance, still to be, Thine eye a survey took; And all my members, yet unformed by thee, Were written in thy book. PSALM CXXXix. 13-16. INTRODUCTION. Of the Organical Sciences THOUGH the general notion of life is acknowledged by the most profound philosophers to be dim and mysterious, even up to the present time; and must, in the early stages of human speculation, have been still more obscure and confused; it was sufficient, even then, to give interest and connexion to men's observations upon their own bodies and those of other animals. It was seen, that in living things, certain peculiar processes were constantly repeated, as those of breathing and of taking food, for example; and that a certain conformation of the parts of the animal was subservient to these processes; and thus were gradually formed the notions of Function and of Organization. And the sciences of which these notions formed the basis are clearly distinguishable from all those which we have hitherto considered. We conceive an organized body to be one in which the parts are there for the sake of the whole, in a manner different from any mechanical or chemical connexion; we conceive a function to be not merely a process of change, but of change connected with the general vital process. When mechanical or chemical processes occur in the living body, they are instrumental to, and directed by, the peculiar powers of life. The sciences which thus consider organization and vital functions may be termed organical sciences. When men began to speculate concerning such subjects, the general mode of apprehending the process in the cases of some functions, appeared to be almost obvious; thus it was conceived that the growth of animals arose from their frame appropriating to itself a part of the substance of the food through the various passages of the body. Under the influence of such general conceptions, speculative men were naturally led to endeavor to obtain more clear and definite views of the course of each of such processes, and of the mode in which the separate parts contributed to it. Along with the observation of the living person, the more searching examination which could be carried on in the dead body, and the comparison of various kinds of animals, soon showed that this pursuit was rich in knowledge and in interest. |