Weismann's views have passed through various stages of remodeling, 392. The Evolution Theory published in 1904 is the best exposition of his views, 392. His theory the field for much controversy. Primarily a theory of heredity, 393. Weismann's theory summarized, 393. Continuity of the germ-plasm the central idea in Weismann's theory, 394. Complexity of the germ-plasm. Illustrations, 395. The origin of variations, 396. The union of two complex germ-plasms gives rise to variations, 396. His extension of the principle of natural selection--germinal selection, 397. The inheritance of acquired characters, 398. Weismann's analysis of the subject the best, 398. Illustrations, 399. The question still open to experimental observation, 399. Weismann's personality, 400. Quotation from his autobiography, 401. The mutation theory of De Vries, 402. An important contribution. His application of experiments commendable, 403. The mutation theory not a substitute for that of natural selection, 404. Tendency toward a reconciliation of apparently conflicting views, 404. Summary of the salient features of the theories of Lamarck, of Darwin, of Weismann, and De Vries, 405. Causes for bewilderment in the popular mind regarding the different forms of the evolution theory, 406. CHAPTER XIX The Rise of Evolutionary Thought, 407 Opinion before Lamarck, 407. Views of certain Fathers of the Church, 408. St. Augustine, 409. St. Thomas Aquinas, 409. The rise of the doctrine of special creation, 410. Suarez, 410. Effect of John Milton's writings, 411. Forerunners of Lamarck: Buffon, Erasmus Darwin, Goethe, 411. Statement of Buffon's views on evolution, 412. Erasmus Darwin the greatest of Lamarck's predecessors, 413. His writings, 414. Paley's Natural Theology directed against them, 414. Goethe's connection with evolutionary thought, 414. Causes for the neglect of Lamarck's theoretical writings, 415. The temporary disappearance of the doctrine of organic evolution, 415. Cuvier's opposition, 415. The debate between Cuvier and St. Hilaire, 415. Its effect, 417. Influence of Lyell's Principles of Geology, 418. Herbert Spencer's analysis in 1852, 419. Darwin and Wallace, 420. Circumstances under which their work was laid before the Linnæan Society of London, 420. The letter of transmission signed by Lyell and Hooker, 420-422. The personality of Darwin, 422. Appearance, 423. His charm of manner, 423. Affectionate consideration at home, 424. Unexampled industry and conscientiousness in the face of ill health, 424, 426. His early life and education, 425. Voyage of the _Beagle_, 425. The results of his five years' voyage, 426. Life at Downs, 426. Parallelism in the thought of Darwin and Wallace, 427. Darwin's account of how he arrived at the conception of natural selection, 427. Wallace's narrative, 428. The Darwin-Wallace