1872.] 'ORIGIN' SIXTH EDITION. 333 



" Finally, I trust that Mr. Hudson is mistaken when he says 

 that any one acquainted with the habits of this bird might be 

 induced to believe that I ' had purposely wrested the truth ' 

 in order to prove my theory. He exonerates me from this 

 charge ; but I should be loath to think that there are many 

 naturalists who, without any evidence, would accuse a fellow- 

 worker of telling a deliberate falsehood to prove his theory." 

 In the sixth edition, p. 142, the passage runs "in certain 

 large districts it does not climb trees." And he goes on to 

 give Mr. Hudson's statement that in other regions it does 

 frequent trees. 



One of the additions in the sixth edition (p. 149), was a 

 reference to Mr. A. Hyatt's and Professor Cope's theory of 

 "acceleration." With regard to this he wrote (October 10, 

 1872) in characteristic words to Mr. Hyatt: 



" Permit me to take this opportunity to express my sincere 

 regret at having committed two grave errors in the last 

 edition of my * Origin of Species,' in my allusion to yours and 

 Professor Cope's views on acceleration and retardation of de- 

 velopment. I had thought that Professor Cope had preceded 

 you ; but I now well remember having formerly read with 

 lively interest, and marked, a paper by you somewhere in my 

 library, on fossil Cephalapods with remarks on the subject. 

 It seems also that I have quite misrepresented your joint 

 view. This has vexed me much. I confess that I have 

 never been able to grasp fully what you wish to show, and I 

 presume that this must be owing to some dulness on my 

 part." 



Lastly, it may be mentioned that this cheap edition being 

 to some extent intended as a popular one, was made to in- 

 clude a glossary of technical terms, " given because several 

 readers have complained. . . . that some of the terms used 

 were unintelligible to them." The glossary was compiled 

 by Mr. Dallas, and being an excellent collection of clear 

 and sufficient definitions, must have proved useful to many 

 readers.] 



