52 AUTOBIOGRAPHY. [ch. ii. 



Many persons have been much interested by this little life, 

 and I am surprised that only 800 or 900 copies were sold. 



In 1880 I published, with [my son] Frank's assistance 

 our Power of Movement in Plants. This was a tough piece 

 of work. The book bears somewhat the same relation to 

 my little book on Climbing Plants, which Gross- Fertilis- 

 ation did to the Fertilisation of Orchids ; for in accord- 

 ance with the principle of evolution it was impossible to 

 account for climbing plants having been developed in so 

 many widely different groups unless all kinds of plants 

 possess some slight power of movement of an analogous 

 kind. This I proved to be the case ; and I was further 

 led to a rather wide generalisation, viz., that the great and 

 important classes of movements, excited by light, the attrac- 

 tion of gravity, &c, are all modified forms of the funda- 

 mental movement of circumnutation. It has always pleased 

 me to exalt plants in the scale of organised beings ; and I 

 therefore felt an especial pleasure in showing how many and 

 what admirably well adapted movements the tip of a root 

 possesses. 



I have now (May 1, 1881) sent to the printers the MS. 

 of a little book on The Formation of Vegetable Mould 

 through the Action of Worms. This is a subject of but 

 small importance ; and I know not whether it will interest 

 any readers,* but it has interested me. It is the comple- 

 tion of a short paper read before the Geological Society 

 more than forty years ago, and has revived old geological 

 thoughts. 



I have now mentioned all the books which I have pub- 

 lished, and these have been the milestones in my life, so that 

 little remains to be said. I am not conscious of any change 

 in my mind during the last thirty years, excepting in one 

 point presently to be mentioned ; nor, indeed, could any 

 change have been expected unless one of general deteriora- 

 tion. But my father lived to his eighty-third year with his 

 mind as lively as ever it was, and all his faculties undimmed ; 

 and I hope that I may die before my mind fails to a sensible 

 extent. I think that I have become a little more skilful in 

 guessing right explanations and in devising experimental 

 tests ; but this may probably be the result of mere practice, 

 and of a larger store of knowledge. I have as much diffi- 

 culty as ever in expressing myself clearly and concisely ; and 



* Between November 1881 and Februaiy 1884, 8500 copies were sold. F. D. 



