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. 
