Survival of the Fittest. 439 
©) 
inhabitants of a country are struggling together with nicely- 
balanced forces, extremely-slight modifications in the 
structure or habits of one species would often give it an 
advantage over others; and still further modifications, so 
long as the species continued under the same conditions of 
life and profited by similar means of subsistence and defence, 
would often still further augment the advantage. No coun- 
try can be mentioned whose native inhabitants are now so 
perfectly adapted to each other and to their environment that 
none could be better adapted and improved, for in all coun- 
tries the natives have been so far conquered by naturalized 
productions as to have allowed them to take firm possession 
of the land. And as foreigners have thus in every country 
beaten some of the natives, it may be safely concluded that 
the latter might have been modified with profit so as to have 
better resisted the intruders. 
A man by his methodical and unconscious means of 
selection can produce and has produced great results. 
What may not Natural Selection effect? Man can only 
operate on external and visible characters, but nature cares 
nothing for appearances, except in so far as they are bene- 
ficial to any being. She can act on every internal organ, 
on every shade of constitutional difference and, in fine, on 
the entire machinery of life. Man selects exclusively for 
his own advantage, but nature solely for that of the being 
she tends, and under her judicious selection the slightest 
difference of structure or constitution may well turn the 
nicely-balanced scale in the Struggle for Existence, and thus 
be preserved. As fleeting as are the wishes and efforts of 
man, and as short as is his earthly career, so poor, therefore, 
must be the results which he accomplishes when compared 
with those accumulated by nature during whole geological 
periods, Is it a wonder, then, that her productions should 
be far ¢ruer in character than man’s, and that they should be 
infinitely better adapted to the most complex conditions of 
life and should bear the stamp of far higher workmanship ? 
