{43} A discussion on the intercrossing of hermaphrodites in relation to Knight's views occurs in the _Origin_, Ed. i. p. 96, vi. p. 119. The parallelism between crossing and changed conditions is briefly given in the _Origin_, Ed. i. p. 267, vi. p. 391, and was finally investigated in _The Effects of Cross and Self-Fertilisation in the Vegetable Kingdom_, 1876. Therefore if in any country or district all animals of one species be allowed freely to cross, any small tendency in them to vary will be constantly counteracted. Secondly reversion to parent form--analogue of _vis medicatrix_{44}. But if man selects, then new races rapidly formed,--of late years systematically followed,--in most ancient times often practically followed{45}. By such selection make race-horse, dray-horse--one cow good for tallow, another for eating &c.--one plant's good lay <illegible> in leaves another in fruit &c. &c.: the same plant to supply his wants at different times of year. By former means animals become adapted, as a direct effect to a cause, to external conditions, as size of body to amount of food. By this latter means they may also be so adapted, but further they may be adapted to ends and pursuits, which by no possibility can affect growth, as existence of tallow-chandler cannot tend to make fat. In such selected races, if not removed to new conditions, and <if> preserved from all cross, after several generations become very true, like each other and not varying. But man{46} selects only <?> what is useful and curious--has bad judgment, is capricious,--grudges to destroy those that do not come up to his pattern,--has no [knowledge] power of selecting according to internal variations,--can hardly keep his conditions uniform,--[cannot] does not select those best adapted to the conditions under which <the> form <?> lives, but those most useful to him. This might all be otherwise. {44} There is an article on the _vis medicatrix_ in Brougham's _Dissertations_, 1839, a copy of which is in the author's library. {45} This is the classification of selection into methodical and unconscious given in the _Origin_, Ed. i. p. 33, vi. p. 38. {46} This passage, and a similar discussion on the power of the Creator (p. 6), correspond to the comparison between the selective capacities of man and nature, in the _Origin_, Ed. i. p. 83, vi. p. 102. Sec. II. <ON VARIATION IN A STATE OF NATURE AND ON THE NATURAL MEANS OF SELECTION.>