Note 53 — Chapter XIII · INHERITANCE continued—REVERSION OF ATAVISM.

Prof. Weismann, in his very curious essay on the different forms produced by the same species of butterfly at different seasons (‘Saison-Dimorphismus der Schmetterlinge,’ pp. 27, 28), has come to a similar conclusion, namely, that any cause which disturbs the organisation, such as the exposure of the cocoons to heat or even to much shaking, gives a tendency to reversion.