This work is a groundbreaking exploration of the laws that govern the introduction of new species. Written during the early days of the study of evolution, this book reflects the author's passionate curiosity about the natural world. This book is essential reading for anyone interested in the history of science and the evolution of our understanding of the world around us. 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.