JST. 66.] TO G. FREDERICK WRIGHT. 667 



how Kingsley caught at my essay, which was reprinted 

 in England long ago ; see his memoirs. 



1877. 



I would say to President Fairchild something like 

 this : 



Where only one individual out of a thousand or 

 a million can survive to maturity and propagation, 

 clearly only the very best adapted to the environment 

 will so survive; and in somewhat different environ- 

 ments, only those best adapted respectively to the 

 two, three, or more different environments. The 

 intermediates, i. e., those least particularly adapted to 

 the two or three different emergencies, surely have 

 least chance. 



Now our species of plants and animals are the com- 

 paratively few surviving lines of a great number of 

 lines which have come down through long and vari- 

 ous periods of great tribulation, in the literal sense 

 of the word ; they have been ground over and over, 

 first on this trial, then on that, leaving, as it seems 

 to me, no chance of the survival, side by side, of all 

 sorts and shades of intermediate forms. Hence, 

 under this, and the general law of heredity, the prac- 

 tical distinction of species and genera appears to be a 

 natural result. 



That low, and even the lowest, forms of life should 

 survive and abound all down the ages, and be the 

 most widely diffused over the earth, seems also the 

 most natural result, being simple adaptations to sim- 

 plest conditions of air and water, so nearly the same 

 the world over. These are still far most numerous in 

 individuals, and have, so to say, the surest hold on 

 life. When we think of the vast void below which 



