Physiology and Hygiene for Secondary Schools by Francis M. Walters, A.M. Edition 1, (November 15, 2005) D.C. Heath and Co. - Publishers Original copyright 1909 "It is quite possible to give instruction in this subject in such a manner as not only to confer knowledge which is useful in itself, but to serve the purpose of a training in accurate observation, and in the methods of reasoning of physical science."—_Huxley._ PREFACE The aim in the preparation of this treatise on the human body has been, first, to set forth in a _teachable_ manner the actual science of physiology; and second, to present the facts of hygiene largely as _applied physiology_. The view is held that "right living" consists in the harmonious adjustment of one’s habits to the nature and plan of the body, and that the best preparation for such living is a correct understanding of the physical self. It is further held that the emphasizing of physiology augments in no small degree the educative value of the subject, greater opportunity being thus afforded for exercise of the reasoning powers and for drill in the _modus operandi_ of natural forces. In the study of physiology the facts of anatomy have a place, but in an elementary course these should be restricted to such as are necessary for revealing the general structure of the body. Although no effort has been spared to bring this work within the comprehension of the pupil, its success in the classroom will depend largely upon the method of handling the subject by the teacher. It is recommended, therefore, that the _relations_ which the different organs and processes sustain to each other, and to the body as a whole, be given special prominence. The pupil should be impressed with the essential unity of the body and should see in the diversity of its activities the serving of a common purpose. In creating such an impression the introductory paragraphs at the beginning of many of the chapters and the summaries throughout the book, as well as the general arrangement of the subject-matter, will be found helpful. Since the custom largely prevails of teaching physiology in advance of the sciences upon which it rests—biology, physics, and chemistry—care should be exercised to develop correct ideas of the principles and processes derived from these sciences. Too much latitude has been taken in the past in the use of comparisons and illustrations drawn from "everyday life." To teach that the body is a "house," "machine," or "city"; that the nerves carry "messages"; that the purpose of oxygen is to "burn up waste"; that breathing is to "purify the blood," etc., may give the pupil phrases which he can readily repeat, but teaching of this kind does not give him correct ideas of his body.