EXPERIMENT. 49 



geological changes is like a mere point in the infinite pro 

 gression of time. When we know that rain water falling 

 on limestone will carry away a minute portion of the 

 rock in solution, we do not hesitate to multiply that quan 

 tity by millions and millions, and assert that in course of 

 time a mountain may be dissolved away. We have actual 

 experience concerning the rise of land in some parts of 

 the globe and its fall in others to the extent of some feet. 

 Do we hesitate to infer what may thus be done in course 

 of geological ages ? As Gabriel Plattes long ago re 

 marked, The sea never resting, but perpetually winning 

 land in one place and losing in another, doth shew what 

 may be done in length of time by a continual operation, 

 not subject unto ceasing or intermission 11 . The action 

 of physical circumstances upon the forms and characters 

 of animals by natural selection is subject to exactly the 

 same remarks. As regards animals living in a state of 

 nature the change of circumstances which can be ascer 

 tained to have occurred is so indefinitely slight, that we 

 could not expect to observe any change in those animals 

 whatever. Nature has made no experiment at all for us 

 within historical times. Man, however, by taming and 

 domesticating dogs, cats, horses, oxen, &c., has made con 

 siderable change in their circumstances, and we find con 

 siderable change also in their forms and character. Sup 

 posing the state of domestication to continue unchanged, 

 these new forms would continue permanent so far as we 

 know, and in this sense they are permanent. Thus the 

 arguments against Darwin s theory, founded on the non- 

 observation of natural changes within the historical period, 

 are of the weakest character, being purely negative. 



11 Discovery of Subtcrraneal Treasure, 1639, p. 52. 



VOL. II. 



