: Darwin and After Darwin Volume 2 of 3 Post-Darwinian Questions: Heredity and Utility by Romanes George John - Evolution (Biology); Heredity

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NOTE A TO PAGE 57 333

NOTE B TO PAGE 89 337

PAGE

Diagram of Prof. Weismann's Theories 43

FIG. 1. Guinea pigs, showing gangrene of ears due to injury of restiform bodies 118

FIG. 2. Old Irish Pig 188

FIG. 3. Skulls of Niata Ox and of Wild White Ox 192

FIG. 4. Lower teeth of Orang 261

INTRODUCTORY: THE DARWINISM OF DARWIN, AND OF THE POST-DARWINIAN SCHOOLS.

The most important of the questions in debate is one which I have already had occasion to mention, while dealing, in historical order, with the objections that were brought against the theory of natural selection during the life-time of Darwin. Here, however, we must consider it somewhat more in detail, and justify by quotation what was previously said regarding the very definite nature of his utterances upon the matter. This question is whether natural selection has been the sole, or but the main, cause of organic evolution.

Part I, pp. 253-256.

Must we regard survival of the fittest as the one and only principle which has been concerned in the progressive modification of living forms, or are we to suppose that this great and leading principle has been assisted by other and subordinate principles, without the co-operation of which the results, as presented in the animal and vegetable kingdoms, could not have been effected? Now Darwin's answer to this question was distinct and unequivocal. He stoutly resisted the doctrine that natural selection was to be regarded as the only cause of organic evolution. On the other hand, this opinion was--and still continues to be--persistently maintained by Mr. Wallace; and it constitutes the source of all the differences between his views and those of Darwin. Moreover, up to the time of Darwin's death, Mr. Wallace was absolutely alone in maintaining this opinion: the whole body of scientific thought throughout the world being against him; for it was deemed improbable that, in the enormously complex and endlessly varied processes of organic evolution, only a single principle should be everywhere and exclusively concerned. But since Darwin's death there has been a great revolution of biological thought in favour of Mr. Wallace's opinion. And the reason for this revolution has been, that his doctrine of natural selection as the sole cause of organic evolution has received the corroborative support of Professor Weismann's theory of heredity--which has been more or less cordially embraced by a certain section of evolutionists, and which appears to carry the doctrine in question as a logical corollary, so far, at all events, as adaptive structures are concerned.

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