CHAPTER XIV. 



[THE few sentences in the autobiographical chapter give 

 with sufficient clearness the connection between the ' Power 

 of Movement,' and one of the author's earlier books, that on 

 ' Climbing Plants.' The central idea of the book is that the 

 movements of plants in relation to light, gravitation, &c., are 

 modifications of a spontaneous tendency to revolve or cir- 

 cumnutate, which is widely inherent in the growing parts of 

 plants. This conception has not been generally adopted, and 

 has not taken a place among the canons of orthodox physi- 

 ology. The book has been treated by Professor Sachs with 

 a few words of professorial contempt ; and by Professor 

 Wiesner it has been honoured by careful and generously ex- 

 pressed criticism. 



Mr. Thiselton Dyer* has well said: "Whether this mas- 

 terly conception of the unity of what has hitherto seemed a 

 chaos of unrelated phenomena will be sustained, time alone 

 will show. But no one can doubt the importance of what 

 Mr. Darwin has done, in showing that for the future the phe- 

 nomena of plant movement can and indeed must be stud- 

 ied from a single point of view." 



The work was begun in the summer of 1877, after the 

 publication of ' Different Forms of Flowers,' and by the 

 autumn his enthusiasm for the subject was thoroughly estab- 

 lished, and he wrote to Mr. Dyer : " I am all on fire at the 

 work." At this time he was studying the movements of 



* ' Charles Darwin ' (' Nature ' Series), p. 41. 



