PREFACE. Vll 



I lecture no more, I still write habitually in a 

 manner suited for oral delivery, and imagine 

 myself speaking to my pupils, if ever I am 

 happily thinking in myself. But it will be 

 also seen that by the help of this very 

 familiarity of style, I am endeavouring, in 

 these and my other writings on Natural 

 History, to compel in the student a clearness 

 of thought and precision of language which 

 have not hitherto been in any wise the virtues, 

 or skills, of scientific persons. Thoughtless 

 readers, who imagine that my own style (such as 

 it is, the one thing which the British public con- 

 cedes to me as a real power) has been formed 

 without pains, may smile at the confidence 

 with which I speak of altering accepted, and 

 even long-established, nomenclature. But the 

 use which I now have of language has taken 

 me forty years to attain ; and those forty 

 years spent, mostly, in walking through the 

 wilderness of this world's vain words, seeking 

 how they might be pruned into some better 

 strength. And I think it likely that at last 

 I may put in my pruning-hook with effect ; 

 for indeed a time must come when English 

 fathers and mothers will wish their children to 



