296 LAY SERMONS, ADDRESSES, AND REVIEWS. [xn. 



for existence and on natural selection, Mr. Darwin does 

 not so much prove that natural selection does occur, as 

 that it must occur ; but, in fact, no other sort of demonstra- 

 tion is attainable. A race does not attract our attention 

 in Nature until it has, in all probability, existed for a 

 considerable time, and then it is too late to inquire into 

 the conditions of its origin. Again, it is said that there 

 is no real analogy between the selection which takes 

 place under domestication, by human influence, and any 

 operation which can be effected by Nature, for man inter- 

 feres intelligently. Eeduced to its elements, this argu- 

 ment implies that an effect produced with trouble by an 

 intelligent agent must, cb fortiori, be more troublesome, if 

 not impossible, to an unintelligent agent. Even putting 

 aside the question whether Nature, acting as she does 

 according to definite and invariable laws, can be rightly 

 called an unintelligent agent, such a position as this is 

 wholly untenable. Mix salt and sand, and it shall puzzle 

 the wisest of men, w r ith his mere natural appliances, to 

 separate all the grains of sand from all the grains of salt ; 

 but a shower of rain will effect the same object in ten 

 minutes. And so, while man may find it tax all his in- 

 telligence to separate any variety which arises, and to 

 breed selectively from it, the destructive agencies inces- 

 santly at work in Nature, if they find one variety to be 

 more soluble in circumstances than the other, will inevit- 

 ably, in the long run, eliminate it. 



A frequent and a just objection to the Lamarckian 

 hypothesis of the transmutation of species is based upon 

 the absence of transitional forms between many species. 

 But against the Darwinian hypothesis this argument has 

 no force. Indeed, one of the most valuable and sugges- 

 tive parts of Mr. Darwin's work is that in which he 

 proves, that the frequent absence of transitions is a ne- 

 cessary consequence of his doctrine, and that the stock 



