Among the examples of ridicule to which Darwin's ideas have been exposed, we cite one verse from the song of Lord Neaves. His lordship wrote a song with a large number of verses hitting off in jocular vein many of the claims and foibles of his time. In attempting to make fun of Darwin's idea he misses completely the idea of natural selection, but hits upon the principle enunciated by Lamarck, instead. He says: "A deer with a neck which was longer by half Than the rest of his family's--try not to laugh-- By stretching and stretching became a giraffe, Which nobody can deny." The clever young woman, Miss Kendall, however, in her _Song of the Ichthyosaurus_, showed clearness in grasping Darwin's idea when she wrote: "Ere man was developed, our brother, We swam, we ducked, and we dived, And we dined, as a rule, on each other. What matter? The toughest survived." This hits the idea of natural selection. The other two illustrations miss it, but strike the principle which was enunciated by Lamarck. This confusion between Lamarckism and Darwinism is very wide-spread. Darwin's book on the _Origin of Species_, published in 1859, was epoch-making. If a group of scholars were asked to designate the greatest book of the nineteenth century--that is, the book which created the greatest intellectual stir--it is likely that a large proportion of them would reply that it is Darwin's _Origin of Species_. Its influence was so great in the different domains of thought that we may observe a natural cleavage between the thought in reference to nature between 1859 and all preceding time. His other less widely known books on _Animals and Plants Under Domestication_, the _Descent of Man_, etc., etc., are also important contributions to the discussion of his theory. A brief account of Darwin, the man, will be found in Chapter XIX. CHAPTER XVIII THEORIES OF EVOLUTION CONTINUED: WEISMANN, DE VRIES Weismann's views have passed through various stages of remodeling since his first public championship of the Theory of Descent on assuming, in 1867, the position of professor of zoölogy in the University of Freiburg. Some time after that date he originated his now famous theory of heredity, which has been retouched, from time to time, as the result of aggressive criticism from others, and the expansion of his own mental horizon. As he said in 1904, regarding his lectures on evolution which have been delivered almost regularly every year since 1880, they "were gradually modified in accordance with the state of my knowledge at the time, so that they have been, I may say, a mirror of my own intellectual evolution."