William Townsend Porter

An Introduction to Physiology William Townsend Porter

Book may have numerous typos, missing text, images, or index. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. 1906. Excerpt: ... INTRODUCTION Until recent times it was believed that many of the compounds found in the tissues of animals and plants could be made only by the action of organized, i. e. living matter. Such compounds were called organic to distinguish them from those found in inorganic or inanimate nature. The forces producing organic compounds were thought to be partly the ordinary chemical and physical processes known to science, and partly certain mystical agencies termed vital forces. The great discovery of Wbhler in 1828 that urea (C02NH2), a typical organic compound, could be made synthetically in the laboratory, overthrew this conception and was the beginning of a long and fruitful struggle to bring the phenomena of living matter within the operation of chemical and physical laws without recourse to the supernatural and occult. According to this new, unified view of nature, which is the foundation of modern physiology, all phenomena, whether animate or inanimate, are alike the expression of chemical and physical processes, some known, some unknown, none of which is fundamentally different from the rest. The physiologist, therefore, now looks upon the reactions of living matter with the eye of the physicist, and it is of the first importance to beginners in physiology to acquire this point of view. To this end it is desirable to consider living tissues from the standpoint of energy and to divide, even imperfectly, the functions to be studied into those that have to do with the income of energy and those that are active in its outgo. These studies cannot, however, be profitably undertaken without some acquaintance with the general properties of living tissues, such as irritability and contractility. We shall begin, therefore, by examining a motor nerve and the muscle in which its fibres are di...