Excerpt from The Principles of Biology, Vol. 2 I think that Prof. Morgan is right. Though at the close of the preface to volume I, I wrote in all sections not marked as new, the essential ideas set forth are the same as they were in the original edition of yet the reader who has not read this statement, or does not bear it in mind, will suppose that all or most of the enunciated conceptions are of recent date, whereas only a small part of them are. I have therefore decided to follow, in this second volume, a course somewhat like that suggested by Prof. Morgan somewhat like, I say, because in sundry cases the amend ments could not be satisfactorily made by appended notes. But there has been a further reason for this change of method. An invalid who is nearly eighty cannot with pru dence enter upon work which will take long to complete. Hence I have thought it better to make the needful altera tions and additions in ways requiring relatively moderate time and labour. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.