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.
33/94 page 23
![§ i. (On Variation under Domestication, and on the Principles of Selection.) An individual organism placed under new con¬ ditions [often] sometimes varies in a small degree and in very trifling respects such as stature, fatness, sometimes colour, health, habits in animals and probably disposition. Also habits of life develope certain parts. Disuse atrophies. [Most of these slight variations tend to become hereditary.] When the individual is multiplied for long periods by buds the variation is yet small, though greater and occasionally a single bud or individual departs widely from its type (example)1 and continues steadily to propagate, by buds, such new kind. When the organism is bred for several genera¬ tions under new or varying conditions, the variation is greater in amount and endless in kind [especially2 holds good when individuals have long been exposed to new conditions]. The nature of the external conditions tends to effect some definite change in all or greater part of offspring,—little food, small size— certain foods harmless &c. &c. organs affected and diseases—extent unknown. A certain degree of 1 Evidently a memorandum that an example should be given. 2 The importance of exposure to new conditions for several generations is insisted on in the Origin, Ed. i. p. 7, also p. 131. In the latter passage the author guards himself against the assumption that variations are “ due to chance,” and speaks of “our ignorance of the cause of each particular variation.” These statements are not always remembered by his critics.](https://iiif.wellcomecollection.org/image/b31351761_0035.jp2/full/800%2C/0/default.jpg)
