WCP7225

[1]¹

CORFE VIEW,

PARKSTONE,

DORSET.

August 16 th. 1891

Dear Mr. Masters

There does not seem to me to be any difficulty in defining "acquired characters" in the senses used by Weismann.¹ They are, — those changes induced by the action of external conditions on all the individuals exposed to them.

Sports,¹ such as your Myosotes, are not due to external conditions acting on the growing or adult organism, because they appear singly or in small numbers, among many [2] normal individuals which have been nevertheless exposed to the same external conditions. The question is of course of immense importance for the theory of development. If distinct races can be formed — and ultimately distinct species — by modifying the conditions under which plants & animals [1 word live, — and careful excluding any selection of sports or of spontaneous individual variations, then Lamarck² was right, and [3] we must greatly modify our conception of the mode of evolution. No doubt experiments to prove the point are difficult, but I do not think the difficulties are by any means insuperable.

My out-of-door heaths (Cape) were of course all killed last winter. It was an unfortunate beginning, — but I may perhaps try again.

Yours very truly | Alfred R. Wallace [signature]