502 LETTERS TO DARWIN AND OTHERS. [1863, 



but clear, and I think useful. I see no occasion for 

 finding fault with him, except in his attempts now 

 and then to direct a little odium against you, which is 

 unhandsome, for his main points are those I hammered 

 out in the " Atlantic," etc. ; indeed I see signs of his 

 having read the same. But it is hardly fair of him, 

 after expressing his complete conviction that where 

 the operation of natural causes can be clearly traced, 

 the implication of design, upon its appropriate evi- 

 dence, is not thereby rendered less certain or less 

 convincing, to go on to speak of derivation-doctrine in 

 a way that implies the contrary. 



Of course we believers in real design make the 

 most of your " frank " and natural terms, " contri- 

 vance, purpose," etc., and pooh-pooh your endeavors 

 to resolve such contrivances into necessary results of 

 certain physical processes, and make fun of the race 

 between long noses and long nectaries ! 



March 23. 



Dr. Wyman, 1 who is a sharp fellow, tells me that, 

 on the authority of the historian Prescott, the Incas 

 of Peru, for no one knows how long, married their 

 sisters, to keep the perfect purity of the blood. 

 Query : How did this strong case of close-breeding 

 operate ? Did they run out thereby ? Wyman thinks 

 there is no evidence of it. 



If it is true, and the Incas stood it for a long 

 course of generations, you must look to it, for it will 

 bear hard against your theory of the necessity of 

 crossing. If they run out, you will have a good case. 



1 Dr. Jeffries Wyman. 



