Ch. II.] EARTHWORMS. 49 



little book on Climbing Plants, which Cross-Fertilisation did 

 to the Fertilisation of Orchids; for in accordance 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, ex- 

 cited by light, the attraction of gravity, &c, are all modified 

 forms of the fundamental 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 completion of a short paper read 

 beforo the Geological Society more than forty years ago, and 

 hns revived old geological thoughts. 



I have now mentioned all the books which I have published, 

 jand 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 pre- 

 sently to be mentioned; nor, indeed, could any change have been 

 expected unless one of general deterioration. 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 difficulty as ever in 

 expressing myself clearly and concisely; and this difficulty 

 has caused me a very great loss of time; but it has had the 

 compensating advantage of forcing me to think long and 

 intently about every sentence, and thus I have been led to 

 see errors in reasoning and in my own observations or those 

 of others. 



There seems to be a sort of fatality in my mind leading 

 me to put at first my statement or proposition in a wrong or 

 awkward form. Formerly I used to think about my sentences 



* Between November 1881 and February 1884, 8500 copies were 

 sold.— F. D. 



