LIFE ON THE EARTH. 185 



the unquestionable power of adaptation which living 

 creatures possess, through exercise of the organs of 

 life, by which some change is possible in structure 

 and some change in function also, the new qualities 

 being in some degree transmitted to the descendants. 



There is no need to mention in detail the views 

 of other and later continental writers, for none have 

 been more ingenious, more plausible, or more ex- 

 plicit; nor has the proof which is wanting to sus- 

 tain the propositions of Lamarck been supplied by 

 his followers in any country. 



The speculations of Lamarck have met with a 

 full and fair examination in Ly ell's Principles of 

 Geology, leading to a deliberate rejection of the hy- 

 pothesis, and a decisive affirmation of the reality of 

 species in nature. The following is his recapitula- 

 tion of the result of the inquiry. 



'For the reasons therefore detailed in this and 

 the two preceding chapters, we may draw the follow- 

 ing inferences in regard to the reality of species in 

 nature : 



1 1. That there is a capacity in all species to 

 accommodate themselves, to a certain extent, to a 

 change of external circumstances, this extent varying 

 greatly, according to the species. 



' 2. When the change of situation which they can 

 endure is great, it is usually attended by some mo- 



