AN INQUIRY INTO THE PROPAGATION OF CONTAGIOUS POISONS, BY THE ATMOSPHERE; AS ALSO INTO THE NATURE AND EFFECTS OF VITIATED AIR, ITS FORMS AND SOURCES, AND OTHER CAUSES OF PESTILENCE; WITH DIRECTIONS FOR AVOIDING THE ACTION OF CONTAGION, AND OBSERVATIONS ON SOME MEANS FOR PROMOTING PUBLIC HEALTH BY S. SCOTT ALISON, M. D. TRANENT. “I have long thought that there is no subject on which a Physician could employ his time and ability more advantageously for the benefit of his fellow-creatures, than in the investigation of febrile Contagion, in order to ascertain the laws by which it is communicated, and by what means it may be prevented.” HAYGARTH EDINBURGH: MACLACHLAN, STEWART & CO.; LONDON, WHITTAKER & CO. 1839. PRINTED BY NEILL AND CO., OLD FISHMARKET, EDINBURGH. PREFACE. The Author trusts that the importance and the accuracy of the facts which have been detailed in the following Work may, in some measure, counterbalance the many defects which will doubtless present themselves to the reader. The progress of the Work has been interrupted, on innumerable occasions, by the unceasing labours incident to the life of a country medical practitioner; and though many of the facts and arguments which have been used, have long obtained the author’s attentive consideration, their reduction to the present form has only now been accomplished during the short intervals which he has seized, after the fatigues of the day had been concluded. The author relies with some confidence on that indulgence which he hopes will be extended to the work of one who contributes, for useful purposes, the results of his experience, derived from an intimate knowledge of the condition, habits, health and diseases of the various classes of the population of a considerable extent of country, of which his situation has put him in possession. S. S. A. TRANENT, _March 1839_. CONTENTS. PART I.