Are the effects of use and disuse inherited? : an examination of the view held by Spencer and Darwin / William Paul Ball.

  • Ball, W. P. (William Platt)
Date:
1890
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Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Are the effects of use and disuse inherited? : an examination of the view held by Spencer and Darwin / William Paul Ball. Source: Wellcome Collection.

    82/178 (page 66)
    66 ARE THE EFFECTS OF USE INHERITED ? (since the pigeons have increased in average size) he compares it with the length of the breast¬ bone in the rock-pigeon.^ By this method if a pigeon had doubled in dimensions while its breast-bone remained imaltered, the reduction would be put down as lOO per cent, whereas obviously the true reduction would be one-half, or 50 per cent, of what the bone should be. Avoiding this error and a minor fallacy besides, a sound estimate reduces the supposed reduction of 13 or 14 per cent, to one of 117 per cent, which is still of course a considerable diminution. Part of this reduction must be due to the direct effect of disuse during the lifetime of the indi¬ vidual. Another and perhaps very consider¬ able part of the relative change must be attri¬ buted to the lengthening of the neck or body by ^ Variation of Animals and Plants under Domestication, i. 184, I suspect that Darwin was in poor health when he wrote this page. He nods at least four times in it. Twice he speaks of twelve breeds where he obviously should have said eleven.