for it. And it is doubtful whether the new theory of "organic selection" will meetmend all the difficulties. The most recent of Weismann's theories, namely that which he calls "general selection" is an attempt in partfact to meetmend theis difficulty and also to account for variations occurring in determinate directions. But we here enter the regions of pure speculation and it is therefore impossible to prove or disprove an hypothesis of this sort.
Another line of argument advanced by Spencer (Appendix to the Principles of Biology, Vol.1) and one which Weismann and his followers have failed to meet satisfactorily, is that derived from (illegible text)Welia's experiments on the sense of touch. The unlikeness of tactual discriminativeness displayed by different parts of the body-surface can be expressed by actual measurements. It is very difficult to explain by natural selection how such a distribution of tactual perceptiveness as is found can have arisen. But if the effects of use are inherited, the facts can be readily accounted for: it is well known from observations made on the blind thattoad the constant exericse of the tactual nervous structures leads to their further development. The same result is well shown in the fingers of compositors.
A case which has been considered by Weismann [1] to afford a very good test is that of the progressive degradation of the human little toe. This had been ascribed by some of those who hold Lamarckian views to the (illegible text) effectsunheeded efforts of the constant boot-pressure. Weismann was able without much difficulty to overthrow this argument. For a
- ↑ The All-Sufficiency of Natural Selection (Contemporary Review, 1893)
