Chapter V: on the basis of these notes, extending it in such ways as

seemed to be desirable. In that case it would have been revised and amended by the author and received his final sanction. Death annulled this friendly compact; and since, had I written the chapter myself, it could not receive that imprimatur which would have given its chief value, I have decided to arrange the material that passed into my hands without adding anything of importance thereto. The substance of Chapters V and VI is therefore entirely the author's: even the phraseology is his; the arrangement only is by another hand.

Such parts of the Preface as more particularly refer to Isolation and Physiological Selection are reserved for publication in Part III. A year or more must elapse before that part will be ready for publication.

Mr. F. Howard Collins has, as a kindly tribute to the memory of the author, read through the proofs. Messrs. F. Darwin, F. Galton, H. Seebohm, and others, have rendered incidental assistance. After much search I am unable to give the references to one or two passages.

I have allowed a too flattering reference to myself to stand, in accordance with a particular injunction of Mr. Romanes given shortly before that sad day on which he died, leaving many to mourn the loss of a personal friend most bright, lovable, and generous-hearted, and thousands to regret that the hand which had written so much for them would write for them no more.

C. LL. M.

UNIVERSITY COLLEGE, BRISTOL, _April, 1894_.

CONTENTS

PAGE CHAPTER I. INTRODUCTORY: THE DARWINISM OF DARWIN AND OF THE POST-DARWINIAN SCHOOLS 1

CHAPTER II. CHARACTERS AS HEREDITARY AND ACQUIRED (_Preliminary_) 39

CHAPTER III.
CHARACTERS AS HEREDITARY AND ACQUIRED (_Continued_)
A. _Indirect evidence in favour of the Inheritance of Acquired
Characters_ 60
B. _Inherited effects of Use and of Disuse_ 95

CHAPTER IV.
CHARACTERS AS HEREDITARY AND ACQUIRED (_Continued_)
C. _Experimental evidence in favour of the Inheritance of Acquired
Characters_ 103

CHAPTER V.
CHARACTERS AS HEREDITARY AND ACQUIRED (_Continued_)
A. and B. _Direct and Indirect Evidence in favour of the
Non-inheritance of Acquired Characters_ 133

C. _Experimental Evidence as to the Non-inheritance of Acquired
Characters_ 142

CHAPTER VI. CHARACTERS AS HEREDITARY AND ACQUIRED (_Conclusion_) 150

CHAPTER VII. CHARACTERS AS ADAPTIVE AND SPECIFIC 159

CHAPTER VIII.
CHARACTERS AS ADAPTIVE AND SPECIFIC (_Continued_)
I. _Climate_ 200
II. _Food_ 217
III. _Sexual Selection_ 219
IV. _Isolation_ 223
V. _Laws of Growth_ 226

CHAPTER IX. CHARACTERS AS ADAPTIVE AND SPECIFIC (_Continued_) 228

CHAPTER X. CHARACTERS AS ADAPTIVE AND SPECIFIC (_Concluded_) 251 SUMMARY 274

APPENDIX I. ON PANMIXIA 291

APPENDIX II. ON CHARACTERS AS ADAPTIVE AND SPECIFIC 307

NOTE A TO PAGE 57 333

NOTE B TO PAGE 89 337

LIST OF ILLUSTRATIONS

PAGE

Portrait of George John Romanes _Frontispiece_

Diagram of Prof. Weismann's Theories 43

FIG. 1. Guinea pigs, showing gangrene of ears due to injury of
restiform bodies 118

FIG. 2. Old Irish Pig (after Richardson) 188

FIG. 3. Skulls of Niata Ox and of Wild White Ox 192

FIG. 4. Lower teeth of Orang (after Tomes) 261