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are as beautiful as those of orchids for ensuring cross-fertilisation. " 

 (I, p. 93.) 



In the midst of all this amount of work, remarkable alike for its 

 variety and its importance, among plants, the animal kingdom was by 

 no means neglected. A large moiety of ' The Variation of Animals 

 and Plants under Domestication' (1868), which contains the pieces 

 justificatives of the first chapter of the ' Origin,' is devotod to domestic 

 animals, and the hypothesis of ' pangenesis ' propounded in the 

 second volume applies to the whole living world. In the ' Origin ' 

 Darwin throws out some suggestions as to the causes of variation, 

 but he takes heredity, as it is manifested by individual organisms, 

 for granted, as an ultimate fact ; pangenesis is an attempt to account 

 for the phenomena of heredity in the organism, on the assumption 

 that the physiological units of which the organism is composed give 

 off gemmules, which, in virtue of heredity, tend to reproduce the 

 unit from which they are derived. 



That Darwin had the application of -his theory to the origin of the 

 human species clearly in his mind in 1859, is obvious from a passage 

 in the first edition of ' The Origin of Species.' (Ed. I, p. 488.) " In 

 the distant future I see open fields for far more important researches. 

 Psychology will be based on a new foundation, that of the necessary 

 acquirement of each mental power and capacity by graduation. 

 Light will be thrown on the origin of man and his history." It is one 

 of the curiosities of scientific literature, that, in the face of this plain 

 declaration, its author should have been charged with concealing his 

 opinions on the subject of the origin of man. But he reserved the full 

 statement of his views until 1871, when the ' Descent of Man ' was 

 published. The ' Expression of the Emotions ' (originally intended to 

 form only a chapter in the 4 Descent of Man ') grew into a separate 

 volume, which appeared in 1872. Although always taking a keen 

 interest in geology, Darwin naturally found no time disposable for 

 geological work, even had his health permitted it, after he became 

 seriously engaged with the great problem of species. But the last 

 of his labours is, in some sense, a return to his earliest, inasmuch as 

 it is an expansion of a short paper read before the Geological Society 

 more than forty years before, and, as he says, " revived old geological 

 thoughts " (I, p. 98). In fact, ' The Formation of Vegetable Mould 

 through the Action of Worms,' affords as striking an example of the 

 great results produced by the long continued operation of small 

 causes as even the author of the ' Principles of Geology ' could have 

 desired. 



In the early months of 1882 Darwin's health underwent a change 

 for the worse ; attacks of giddiness and fainting supervened, and on 

 the 19th of April he died. On the 24th, his remains were interred in 

 Westminster Abbey, in accordance with the general feeling that such 



