INAUGURAL LECTURE ON BOTANY, CONSIDERED AS A SCIENCE, AND AS A BRANCH OF MEDICAL EDUCATION. READ IN KING'S COLLEGE, LONDON, MAY 8th, 1843. BY EDWARD FORBES, F.L.S., F.B.S., VICE-PRESIDENT OF THE WERNERIAN NATURAL HISTORY SOCIETY, ETC.; MR. PRINCIPAL AND GENTLEMEN, ONE of the last friends from whom I parted before leaving England two years ago on a voyage of research in the East, was the distinguished and much-lamented botanist whom I have the high but melancholy honour of succeeding in this chair. His last words on that occasion were instructions for my guidance during a proposed investigation of the natural history of the Archipelago and Asia Minor. The great knowledge which he possessed of botanical science was freely and enthusiastically imparted to all who had the pleasure and benefit of his acquaintance. In the place of that knowledge and experience, I fear I can only offer a fervent attachment to his favourite pursuit, and a determination energetically to labour in the service of this noble Institution. The duties of the Botanical Professorship are, the teaching of Botany as a science, and as a branch of medical education. Being rather an ally than a province of medicine, it forms a connecting link between professional and purely scientific studies. The nature of the subjects of which it treats, requires that it should be numbered among the studies of the Summer Session, when it is honourably associated in the medical department with forensic medicine and practical chemistry. In this introductory lecture I propose, with your permission, to offer a few remarks on the Natural-History sciences generally, and on Botany in particular, as branches of medical education; to take a brief view of the relations of Botany to other pursuits; and to offer some considerations upon the science, and upon the principles of acquiring a knowledge of it. The Natural-History sciences are three :-ZOOLOGY treating of the animal kingdom, BOTANY of the vegetable, and MINERALOGY of the inorganic bodies abounding in nature. These three are united by the inquiries of GEOLOGY, which is rather an exposition of their mutual connexion than a separate science of itself. It may be looked upon as the history of the earth's changes during its preparation for the reception of organized beings, and of the causes which determined the order of their appearance-the proemium of the history of MAN. The biological sciences, zoology and botany, are intimately related to physiology and anatomy; and the more those sciences advance, the closer will be the connexion. In the most remote divisions of the animal and vegetable kingdoms, we find the keys which enable us to lay open and understand the mysteries of vital phænomena. Through a knowledge of the structure of a simple polype we may comprehend more clearly the complicated machinery of the body of man; and the observation of the origin and development of a seed may throw light upon one of the most intricate functions in the animal economy. The views of systematic botany and of systematic zoology are fast attaining a parallelism which must end in the discovery and development of great general laws common to both. The two great kingdoms of organized nature seem to spring, as it were, from one root, and to branch out into correspondent trunks, which, even at their most distant ramifications, exhibit mutual analogies. The lowest forms of each so closely approximate as to furnish subjects for continual discussion; and the number of species, the position of which, whether in the animal or vegetable kingdom, is as yet disputed or undetermined, proves the close alliance of the animal and vegetable natures toward the point of union. Creatures which Ehrenberg figures as animalcules, Meyen describes as plants; and naturalists have not yet ceased debating on the nature of sponges and corallinæ. As we ascend in each great series, the animal or vegetable nature of their respective members becomes more and more decided and unquestionable, while there is still retained a close resemblance of external form. Thus a Mucor, an Agaricus and a Sphæria image, as it were, their parallels and yet opposites, a Hydra, a Medusa and an Echinus. Ascending higher we find all resemblance of form disappear, but still there is a true analogy. The exoskeleton of the Monocotyledones represents, though far and faintly, the exoskeleton of the Articulata ; and the endoskeleton of the Dicotyledones the same great modification of structure in the Vertebrata. Both kingdoms seem pervaded by a double representation of each other, two great spheres, as it were, repeated within themselves; a representation which will in all probability be found as true in the minor as in the major groups of organized beings. Very different laws regulate the mineral kingdom. Life absent, all the wonderful structures which result from its formative presence have disappeared. Aggregation is but a faint remembrancer of assimilation, and crystallization of organization. The laws of chemistry take the place of the laws of physiology, and it is in the laboratory that a great and important portion of the observations of the mineralogist must be conducted. Those who would gain a sound knowledge of the inorganic substances found in nature, should avail themselves of the instructions and exercises of the practical chemistry class-room as a preliminary study of essential importance; one too of no small consequence to the biologist, as well as absolutely necessary to the physician. In all the natural-history sciences the process of inquiry is the same. A close and patient investigation of structure is entered into, and a careful examination and comparison of forms with a view to the grouping of them in natural assemblages, the right understanding of which exposes to us the |