In this book, Elie Metchnikoff presents three lectures on the prevention of infectious diseases. Metchnikoff was a Russian biologist who won the Nobel Prize in Physiology or Medicine in 1908 for his work on immunity. He believed that good hygiene and nutrition could prevent disease and extend life. The lectures cover topics such as the role of microbes in disease, the importance of cleanliness, and the benefits of vaccination. An informative and timely book for anyone interested in public health. This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work is in the "public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.