1 8 Permanence and Evolution. 



of land from sea, we do not scruple to 

 suppose slow processes of rise or fall, which 

 we know to have gone on for hundreds of 

 years, to have gone on for thousands or 

 millions ; but it is doubtful whether we may 

 make an analogous supposition as to living 

 organisms. We are only justified in going be- 

 yond the naked results of experience when we 

 understand the laws by which the part of nature 

 we are dealing with is regulated. Now this we 

 know, speaking generally in proportion to the 

 degree to which these laws are simple. But 

 nothing in nature is regulated by such a 

 complex of little known laws as a living 

 organism ; therefore, it is much less safe to 

 travel beyond the mere data of experience here 

 than in any other departments of nature, which 

 are simple and better known. No one who was 

 employed in sawing through a granite column, 

 and who found that he got through an inch in 

 a month, would doubt the possibility of his 



