Now let me return to the recent division of biological opinion into two main streams--Lamarckism and Weismannism. Both Lamarckians and Weismannists, not to mention mankind in general, admit that the better adapted to its surroundings a living form may be, the more likely it is to outbreed its compeers. The world at large, again, needs not to be told that the normal course is not unfrequently deflected through the fortunes of war; nevertheless, according to Lamarckians and Erasmus-Darwinians, habitual effort, guided by ever- growing intelligence--that is to say, by continued increase of power in the matter of knowing our likes and dislikes--has been so much the main factor throughout the course of organic development, that the rest, though not lost sight of, may be allowed to go without saying. According, on the other hand, to extreme Charles-Darwinians and Weismannists, habit, effort and intelligence acquired during the experience of any one life goes for nothing. Not even a little fraction of it endures to the benefit of offspring. It dies with him in whom it is acquired, and the heirs of a man's body take no interest therein. To state this doctrine is to arouse instinctive loathing; it is my fortunate task to maintain that such a nightmare of waste and death is as baseless as it is repulsive. The split in biological opinion occasioned by the deadlock to which Charles-Darwinism has been reduced, though comparatively recent, widens rapidly. Ten years ago Lamarck's name was mentioned only as a byword for extravagance; now, we cannot take up a number of Nature without seeing how hot the contention is between his followers and those of Weismann. This must be referred, as I implied earlier, to growing perception that Mr. Darwin should either have gone farther towards Lamarckism or not so far. In admitting use and disuse as freely as he did, he gave Lamarckians leverage for the overthrow of a system based ostensibly on the accumulation of fortunate accidents. In assigning the lion's share of development to the accumulation of fortunate accidents, he tempted fortuitists to try to cut the ground from under Lamarck's feet by denying that the effects of use and disuse can be inherited at all. When the public had once got to understand what Lamarck had intended, and wherein Mr. Charles Darwin had differed from him, it became impossible for Charles-Darwinians to remain where they were, nor is it easy to see what course was open to them except to cast about for a theory by which they could get rid of use and disuse altogether. Weismannism, therefore, is the inevitable outcome of the straits to which Charles-Darwinians were reduced through the way in which their leader had halted between two opinions.