Darbase Darwin union manuscripts catalog
Cambridge University Library DAR 208: 39e
Notebook D: 101,102, 133-136 (excised pages)
D 135e
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population in increase at geometrical ratio in FAR SHORTER time than 25 years— yet until the one sentence of Malthus no one clearly perceived the great check amongst men.—1 «Even a few years plenty, makes population in Men increase,2 & an ordinary crop. causes a dearth then in Spring, like food used for other purposes as wheat for making brandy.—» take Europe on an average, every species must have same number killed, year with year, by hawks. by. cold &c— .. even one species of hawk decreasing in number must effect instantaneously all the rest.— One may say there is a force like a hundred thousand wedges trying force into every kind of adapted structure into the gaps of in the œconomy of Nature, or rather forming gaps by thrusting out weaker ones. «The final cause of all this wedgings, must be to sort out proper structure & adapt it to change.—3 to do that, for form, which Malthus shows, is the final effect, (by means however of volition) of this populousness, on the energy of Man4»

page crossed pencil
Reproduced with the permission of the Syndics of Cambridge University Library and William Huxley Darwin
Transcription and apparatus by the Darwin Manuscripts Project © American Museum of Natural History
  • 1. Malthus 1826, 1:5, 'In the northern states of America, where the means of subsistence have been more ample, the manners of the people more pure, and the checks to early marriages fewer, than in any of the modern states of Europe, the population has been found to double itself, for above a century and half successively, in less than twenty-five years. Yet, even during these periods, in some of the towns, the deaths exceeded the births, a circumstance which clearly proves that, in those parts of the country which supplied this deficiency, the increase must have been much more rapid than the general average.' The single sentence that caught Darwin's attention may have been: 'It may safely be pronounced, therefore, that population, when unchecked, goes on doubling itself every twenty-five years, or increases in a geometrical ratio.' (1:6). Or: 'A thousand millions are just as easily doubled every twenty-five years by the power of population as a thousand. But the food to support the increase from the greater number will by no means be obtained with the same facility. Man is necessarily confined in room.' (1:7).
  • 2. See Malthus 1826, 1:18−19, which discusses the dynamics of population oscillations, '. . . ultimately the means of subsistence may become in the same proportion to the population, as at the period from which we set out. The situation of the labourer being then again tolerably comfortable, the restraints to population are in some degree loosened; and, after a short period, the same retrograde and progressive movements, with respect to happiness, are repeated.'
  • 3. This passage is Darwin's first formulation of natural selection, particularly as the origin of adaptation. It is unambiguously crystallized by his reading of Malthus on 28 September 1838. Darwin completed reading Malthus 1826 on 2−3 October. (See E3, 'Journal', and 'Books examined with ref. to Species.—' C 270: 'October 3d Malthus on Population'). The theory continued to take form in Notebook E.
  • 4. See Malthus 1826, 1:94−95. 'The combined causes soon produce their natural and invariable effect, an extended population. A more frequent and rapid change of place then becomes necessary. A wider and more extensive territory is successively occupied. A broader desolation extends all around them. Want pinches the less fortunate members of society: and at length the impossibility of supporting such a number together becomes too evident to be resisted. Young scions are then pushed out from the parent stock, and instructed to explore fresh regions, . . . Restless from present distress, flushed with the hope of fairer prospects, animated with the spirit of hardy enterprise, these daring adventurers are likely to become formidable adversaries to all who oppose them. The inhabitants of countries long settled, engaged in the peaceful occupations of trade and agriculture, would not often be able to resist the energy of men acting under such powerful motives of exertion. And the frequent contests with tribes in the same circumstances with themselves, would be so many struggles for existence . . .'