vi Preface. 



and xxiii), and in four letters to Nature (vol. xli. 

 p. 536 ; vol. xlii. pp. 28 and 369 ; and vol. xliv. 

 p. 29). 



I have to thank Mr. Francis Galton. D.C.L., F.R.S. 

 and Mr. F. Howard Collins for valuable assistance 

 generously rendered for the sake of one whom all 

 who knew him held dear. For he was, if I may 

 echo the words of Huxley, " a friend endeared to 

 me, as to so many others, by his kindly nature, and 

 justly valued by all his colleagues for his powers 

 of investigation and his zeal for the advancement of 



science." 



C. LLOYD MORGAN. 

 BRISTOL, May 1897. 



