98 AUTOBIOGRAPHY. 



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 ' Cross-Fertilisation ' did to the * Fertilisation of 

 Orchids ; ' for in accordance with the principle of evo- 

 lution 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 

 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 i, 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 inte- 

 rested me. It is the completion 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 

 published, and these have been the milestones in my 



* Between November 1881 and February 1884, 8500 copies have been 

 sold. 



