The various hints and manifestations of earlier evolutionary theory are admirably elucidated in Professor Osborn’s ‘From the Greeks to Darwin.’ The vast curiosity and reflection of Aristotle anticipated here, as everywhere, and some of his sentences have a striking evolutionary bearing: ‘Variety in animal life may be produced by variety of locality.’[389] ‘Locality will differentiate habits also; for instance, rugged highlands will not produce the same results as the soft lowlands.’[390] And Empedocles suggests Darwin’s views even more directly. Under the régime of Biblical and Christian tradition evolutionary thought naturally made little progress. But with the greater freedom of the eighteenth century, notions of modification by descent again appeared. In England Darwin’s grandfather, Erasmus, the botanical poet, speculated curiously on the subject, and there were various other intimations, notably in Chambers’s ‘Vestiges of Creation,’ while Darwin himself felt that he was much influenced by the geological theories of Lyell. In Germany Goethe became profoundly interested in the metamorphoses of life. Especially in France Buffon and St.-Hilaire led up to the ‘Philosophie Zoologique’ of Lamarck, which propounded the theory of modification in a very definite form, and suggested the mode in which the modification was accomplished. Lamarck’s idea was that plants and animals, by an inborn, vital impulse, adapted themselves to their environment, and that these adaptations were transmitted by inheritance. Thus wading birds acquired webbed feet and the neck of the giraffe was elongated in its effort to obtain its food from the branches of the trees. The great stumbling-block of this theory has always been the difficulty of proving that acquired adaptations are inherited.[A] [A] Investigators have of course worked constantly and persistently upon this point and I find Professor William McDougall quoted in a Boston _Herald_ editorial of August 16, 1926, as saying: ‘Species may change and undergo evolution through the efforts of the individual parents to adapt themselves to conditions.’