The Wallace-Darwin Correspondence 



leaf of its food-plant. Many butterfly pupge are known to 

 have the power of individual adjustment to the colours of 

 the particular food-plant or other normal environment ; and 

 it is probable that the Australian Papilio referred to by 

 Darwin possesses this power. 



Nutwood Cottage^ Frith Hill, Godalming. July 9, 1881. 



My dear Darwin, — I am just doing, what I have rarely 

 if ever done before — reading a book through a second time 

 immediately after the first perusal. I do not think I have 

 ever been so attracted by a book, with perhaps the exception 

 of your " Origin of Species '' and Spencer's ** First Prin- 

 ciples '' and " Social Statics. '' I wish therefore to call 

 your attention to it, in case you care about books on social 

 and political subjects, but here there is also an elaborate 

 discussion of Malthus's ^^ Principles of Population," to 

 which both you and I have acknowledged ourselves in- 

 debted. The present writer, Mr. George, while admitting 

 the main principle as self-evident and as actually operat- 

 ing in the case of animals and plants, denies that it ever 

 has operated or can operate in the case of man, still less 

 that it has any bearing whatever on the vast social and 

 political questions which have been supported by a refer- 

 ence to it. He illustrates and supports his views with a 

 wealth of illustrative facts and a cogency of argument 

 which I have rarely seen equalled, while his style is equal 

 to that of Buckle, and thus his book is delightful reading. 

 The title of the book is *^ Progress and Poverty.^' It has 

 gone through six editions in America, and is now published 

 in England by Kegan Paul. It is devoted mainly to a 

 brilliant discussion and refutation of some of the most 

 widely accepted maxims of political economy, such as the 

 relation of wages and capital, the nature of rent and in- 

 terest, the laws of distribution, etc., but all treated as 



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