Produced by Chris Curnow, Lindy Walsh, Greg Bergquist and the Online Distributed Proofreading Team at http://www.pgdp.net Transcriber's Note The punctuation and spelling from the original text have been faithfully preserved. Only obvious typographical errors have been corrected. [Illustration: An artificial lake, nearly dry and partly filled with rubbish, has become a breeding-ground for dangerous mosquitoes.] American Nature Series Group IV. Working with Nature INSECTS AND DISEASE A POPULAR ACCOUNT OF THE WAY IN WHICH INSECTS MAY SPREAD OR CAUSE SOME OF OUR COMMON DISEASES WITH MANY ORIGINAL ILLUSTRATIONS FROM PHOTOGRAPHS BY RENNIE W. DOANE, A.B. _Assistant Professor of Entomology Leland Stanford Junior University_ LONDON CONSTABLE & COMPANY LIMITED 1910 COPYRIGHT, 1910, BY HENRY HOLT AND COMPANY _Published August, 1910_ THE QUINN & BODEN CO. PRESS RAHWAY, N.J. PREFACE The subject of preventive medicine is one that is attracting world-wide attention to-day. We can hardly pick up a newspaper or magazine without seeing the subject discussed in some of its phases, and during the last few years several books have appeared devoted wholly or in part to the ways of preventing rather than curing many of our ills. Looking over the titles of these articles and books the reader will at once be impressed with the importance that is being given to the subject of the relation of insects to some of our common diseases. As many of these maladies are caused by minute parasites or microbes the zoölogists, biologists and physicians are studying with untiring zeal to learn what they can in regard to the development and habits of these organisms, and the entomologists are doing their part by studying in minute detail the structure and life-history of the insects that are concerned. Thus many important facts are being learned, many important observations made. The results of the best of these investigations are always published in technical magazines or papers that are usually accessible only to the specialist. This little book is an attempt to bring together and place in untechnical form the most important of these facts gathered from sources many of which are at present inaccessible to the general reader, perhaps even to many physicians and entomologists. In order that the reader who is not a specialist in medicine or entomology may more readily understand the intimate biological relations of the animals and parasites to be discussed it seems desirable to call attention first to their systematic relations and to review some of the important general facts in regard to their structure and life-history. This, it is believed, will make even the most complex special interrelations of some of these organisms readily understandable by all. Those who are already more or less familiar with these things may find the bibliography of use for more extended reading.