The book is dedicated to that group of freethinkers, including d’Alembert, Diderot, Holbach, and Voltaire, who first dared to follow the consequences of a mechanistic science—incomplete as it then was—to the rules of human conduct and who thereby laid the founda­tion of that spirit of tolerance, justice, and gentleness which was the hope of our civiliza­tion until it was buried under the wave of homicidal emo­tion which has swept through the world. Diderot was singled out, since to him the words of Lord Morley are devoted, which, however, are more or less characteristic of the whole group.

J. L.

The Rockefeller Institute
for Medical Research,
August, 1916

CONTENTS

PAGE
CHAPTER I
Introductory Remarks1
CHAPTER II
The Specific Difference between Living and Dead Matter and the Ques­tion of the Origin of Life14
CHAPTER III
The Chemical Basis of Genus and Species:40
II.—The Incompatibility of Species not Closely Related44
II.—The Chemical Basis of Genus and Species and of Species Specificity53
CHAPTER IV
Specificity in Fertilization71
CHAPTER V
Artificial Parthenogenesis95
CHAPTER VI
Determinism in the Formation of an Organism from an Egg128
CHAPTER VII
Regenera­tion153
CHAPTER VIII
Determina­tion of Sex, Secondary Sexual Characters, and Sexual Instincts:
II.—The Cytological Basis of Sex Determination198
II.—The Physiological Basis of Sex Determination214
CHAPTER IX
Mendelian Heredity and its Mechanism229
CHAPTER X
Animal Instincts and Tropisms253
CHAPTER XI
The Influence of Environment286
CHAPTER XII
Adapta­tion to Environment318
CHAPTER XIII
Evolu­tion346
CHAPTER XIV
Death and Dissolution of the Organism349
Index371

The Organism as a Whole

CHAPTER I