In arranging my material I have followed a roughly chronological sequence, but the character and variety of my father's researches make a strictly chronological order an impossibility. It was his habit to work more or less simultaneously at several subjects. Experimental work was often carried on as a refreshment or variety, while books entailing reasoning and the marshalling of large bodies of facts were being written. Moreover many of his researches were dropped only to be resumed after years had elapsed. Thus a chronological record of his work would be a patchwork, from which it would be difficult to disentangle the history of any given subject. The Table of Contents will show how I have tried to avoid this result. It will be seen, for instance, that after Chapter VIII. a break occurs; the story turns back from 1854 to 1831 in order that the Evolutionary chapters which follow may tell a continuous story. In the same way the Botanical Work which occupied so much of my father's time during the latter part of his life is treated separately in Chapters XVI. and XVII.
With regard to Chapter IV., in which I have attempted to give an account of my father's manner of working, I may be allowed to say that I acted as his assistant during the last eight years of his life, and had therefore an opportunity of knowing something of his habits and methods.
My acknowledgments are gladly made to the publishers of the Century Magazine, who have courteously given me the use of one of their illustrations for the heading of Chapter IV.
FRANCIS DARWIN.
Wychfield, Cambridge,
August, 1892.
FOOTNOTE:
[1] I have not thought it necessary to indicate all the omissions in the abbreviated letters.
NOTE TO THE SECOND EDITION.
It is pleasure to me to acknowledge the kindness of Messrs. Elliott & Fry in allowing me to reproduce the fine photograph which appears as the frontispiece to the present issue.