The foundations of The origin of species : a sketch written in 1842 / edited by Francis Darwin.
- Charles Darwin
- Date:
- 1909
Licence: Public Domain Mark
Credit: The foundations of The origin of species : a sketch written in 1842 / edited by Francis Darwin. Source: Wellcome Collection.
47/94 page 15
![Before leaving this subject well to observe that it was shown that a certain amount of variation is consequent on mere act of reproduction, both by buds and sexually,—is vastly increased when parents exposed for some generations to new conditions1, and we now find that many animals when exposed for first time to very new conditions, are (as) incapable of breeding as hybrids. It [probably] bears also on supposed fact of crossed animals when not infertile, as in mongrels, tending to vary much, as likewise seems to be the case, when true hybrids possess just sufficient fertility to propagate with the parent breeds and inter se for some generations. This is Koelreuter’s belief. These facts throw light on each other and support the truth of each other, we see throughout a connection between the reproduc¬ tive faculties and exposure to changed conditions of life whether by crossing or exposure of the indi¬ viduals2. Difficulties on theory of selection3. It may be objected such perfect organs as eye and ear, could never be formed, in latter less difficulty as gradations more perfect; at first appears mon¬ strous and to (the) end appears difficulty. But think of gradation, even now manifest, (Tibia and Fibula). Everyone will allowif every fossil preserved, gradation have been intended to replace an earlier sentence. I have thought it best to give both. In the Origin, Ed. i. p. 141, vi. p. 176, the author gives his opinion that the power of resisting diverse conditions, seen in man and his domestic animals, is an example “ of a very common flexibility of con¬ stitution.” 1 In the Origin, Ed. i. Chs. i. and v., the author does not admit repro¬ duction, apart from environment, as being a cause of variation. With regard to the cumulative effect of new conditions there are many passages in the Origin, Ed. i. e.g. pp. 7, 12, vi. pp. 8, 14. 2 As already pointed out, this is the important principle investigated in the author’s Gross and Self-Fertilisation. Professor Bateson has suggested to me that the experiments should be repeated with gametically pure individuals. 3 In the Origin a chapter is given up to “ difficulties on theory ”: the discussion in the present essay seems slight even when it is remembered how small a space is here available. For Tibia &c. see p. 48.](https://iiif.wellcomecollection.org/image/b31351761_0049.jp2/full/800%2C/0/default.jpg)
