PREFACE THIS volume consists of a series of lectures delivered by the late Professor Marshall in connection with the Extension Lectures of the Victoria University during the year 1893. These have been amplified in some places where occasion required from other unpublished lectures by the same author. Owing to the variable nature of the original MS., some parts being fully written, while others were in the form of notes, there is a consequent variability in the fulness of the text, and any errors or discrepancies should be attributed to the editor and not the author. It is greatly to be regretted that these Lectures were not elaborated and prepared for publication by the author himself; but, in spite of the shortcomings of the book, I trust that it may form a useful contribution to the literature of Darwinism, since the Lectures were delivered by one of Darwin's most earnest disciples. The large majority of the illustrations are taken from original drawings by the author, or from photographs from nature. Some of the drawings are modified from other sources, and in these cases the source has been acknowledged. The blocks for the illustrations have been prepared with great care by Messrs. Walker & Boutall. In preparing this book I have received valuable assistance from Mr. W. E. Hoyle, Dr. C. H. Hurst, Professors Hickson and Herdman, and Mr. W. Garstang. I must also thank Mr. Francis Darwin for permission to reproduce the extracts in Lecture VIII. LONDON, October 1894. C. F. M. CONTENTS The Earlier Naturalists. Aristotle, 384-322, B.C. Slow accumulation Linnæus, 1707-1778. Introduction of the Binary System of nomen- clature. Birth of the Species Question. Illustrations of the meaning of the word, Species. Linnæus' views on the Origin of Buffon, 1707-1788. Contemporary with Linnæus. The first to Cuvier, 1769-1832. The founder of comparative anatomy, and the first to realise the true value of fossils: a man of commanding power. Cuvier's doctrine of catastrophism, or of periodical annihilation of animal life. A stout supporter of the immutability Goethe, 1790. Essay on the Metamorphosis of Plants. Lamarck, 1744-1829. A colleague of Cuvier. A strong upholder of the doctrine of Evolution: denies the occurrence of Cuvier's cataclysmal revolutions, and maintains the derivation of all organisms from some few simple forms. Geoffroy St. Hilaire, 1771-1840. Like Lamarck a supporter of the Hutton, 1726-1797. Theory of the Earth. Lyell, 1797-1875. The rise of Geology. The doctrine of Uni- competent to produce the present condition of things, but must The Doctrine of Evolution: its gradual spread. Herbert Spencer's General sketch of the life and work of Darwin and Wallace. Simultaneous announcement of the Theory of Natural Selection ARTIFICIAL AND NATURAL SELECTION. The breeding of domestic animals by Artificial Selection. The characters of the principal breeds of domestic pigeons: pouter, carrier, barb, fantail, turbit, tumbler. Evidence in support of the descent of the various breeds of domes- tic pigeons from the wild rock-pigeon, Columba livia. The principles and practice of breeding animals. Variation with heredity. The power and efficiency of Artificial Selection. The There are in nature causes which act in much the same way as man acts, when selecting artificially the best animals for breeding purposes; causes which must lead to structural modifications. The tendency to rapid increase of numbers. Rapid multiplication The causes tending to keep the numbers stationary on the average. The struggle for existence applies to all animals and at all times. Variation: its universal occurrence. Variation occurs in all direc- |