To set fixed limits to the subject matter of physiology is a very difficult task, because, properly conceived,, large portions of the entire group of medical and biological sciences belong to its province. A text-book designed primarily for medical students can, however, regard the field as somewhat more restricted; for the prospective physician has abundant opportunity to amplify his knowledge of the bodily functions from his other studies. Hence in this book I have followed the usual custom and have brought together only so much of our information respecting the human body as can be described as pertaining to its normal functions. The discoveries made in the realms of practical medicine, of experimental pathology and of pharmacology, which in many respects are so full of significance for the processes of the body, are, therefore, for the most part passed by. In like manner the facts of comparative physiology have been alluded to only in exceptional cases, since an exhaustive discussion of them would have increased the size of the book to a not inconsiderable extent. For the same reason I have been unable to find a place for the short histological discussion customary in text-books. I do not regard this as an error, for a necessarily brief and superficial resume of the most important histological facts could be of no great service, since the student needs a more extensive knowledge of the finer structure of the body and must in any case obtain this from the text-books devoted especially to that subject. I do not therefore at all mistake the great importance of histology for physiology; on the contrary, I would recommend that in the study of a text-book of this science a text-book of histology (and one of anatomy) be always at hand in order to combine the physiological facts with the histological and anatomical facts. Physiological chemistry also has develop
(Typographical errors above are due to OCR software and don't occur in the book.)