644 TRAVEL IN EUROPE AND AMERICA. [1873, 



studied the subject think that the increase of pop- 

 ulation in North America is not to go on at the rate 

 it has been going ; that the check is already apparent. 



A week or two ago appeared in the " Nation " an ar- 

 ticle (sent to you last week by post), in which I had 

 occasion to notice some other parts of your volume, 

 at considerable length. I have also been tempted to 

 give some account of your essay on Natural Selection 

 as applied to man ; but I find it would take me too 

 much out of my own line, and absorb time which I 

 cannot spare. Indeed, I have only looked over that 

 essay, and am not qualified to abstract, still less to 

 criticise it. The longest article of the volume, which 

 gives the title, I have not given as much attention to 

 as I ought, probably, or I should perhaps value it 

 more highly. But it seems to me that membership in 

 scientific academies the three you take not ex- 

 cepted is so largely affected by circumstance, irre- 

 spective of talent and of the value of work done, that 

 one cannot very confidently base general conclusions 

 upon the data. Yet I have no great confidence in my 

 opinion. Anyway, the article is full of interesting 

 matters. . . . 



What do you and Dr. Miiller say to Bornet's 

 memoir, on the nature of lichens ? His exposition 

 is so clear that, if he is an honest and good investi- 

 gator, as I cannot well doubt, his conclusions 

 carry conviction. 



My sheet fills, and leaves now barely room for Mrs. 

 Gray's messages of kindest remembrances to yourself 

 and to Madame De Candolle, in which I beg to join. 

 Long may you flourish, and much good work yet 

 do. For one thing, pray print the list of botanical 

 names ! Ever yours, A. GRAY. 



