Copyright, 1901, by W. B. SAUNDERS & COMPANY. Registered at Stationers' Hall, London, England. ELECTROTYPED BY PRESS OF W. B. SAUNDERS & COMPANY. 1643 4131 1401 PREFACE TO SECOND EDITION. IN presenting a second edition of this book I wish to acknowledge my appreciation of the cordial reception given to the first, and to express my indebtedness for the many important criticisms and suggestions that have reached me through reviews and personal communications. The original plan of the book has not been altered, though numerous additions have been made, and, wherever advisable, opinions formerly expressed have been modified to conform with the results of more recent observations and investigations. During the interval that has elapsed since the appearance. of the first edition, investigations upon the modes of dissemination of certain of the specific infections have been conspicuously active, and through them much new light has been shed and many novel suggestions have been made; especially is this the case with regard to the rôles of insects and rodents as disseminating factors. Wherever practicable, these views have been embodied and discussed. The sections especially on Malaria, Yellow Fever, Plague, Filariasis, Dysentery, and Tuberculosis have been both revised and enlarged. To keep the book within a reasonably small compass, much that is of interest must of necessity be omitted; but it is to be hoped that most of that which is of fundamental importance to the subject may be found within its pages. A. C. A. LABORATORY OF HYGIENE, UNIVERSITY OF PENNSYLVANIA, Philadelphia, April, 1901. PREFACE. THE Contents of this book are essentially the subject-matter of a portion of my lectures on General Hygiene at the University of Pennsylvania. It is not the purpose of this work to present the subject of Hygiene in the comprehensive sense ordinarily implied by the word, but rather to deal directly with but a section, certainly not the least important, of the subject-viz., that embracing a knowledge of the preventable specific diseases. Incidentally, as occasion may require, there are discussed those numerous and various factors that have not only a direct bearing upon the incidence and suppression of such diseases, but that are of general sanitary importance as well. In the preparation of this work only the most trustworthy authors have been consulted, and only those precepts embodied that are now generally accepted by sanitarians as sound. It will be manifest to the reader that a great deal is still wanting to complete our knowledge upon many important phases of the subject, and no effort has been made to disguise this fact. The frequency with which requests are received for information concerning the detailed management of transmissible diseases is in part the reason for the publication of this book. I trust the work may serve a useful purpose. A. C. A. |