14 On Some Interactions of Organisms. 
tempts to set it aside more or less completely. In the pas- 
ture and meadow, it answers our purpose to substitute 
other species for the grasses growing there spontaneous- 
ly, and these adapt themselves easily to the circum- 
stances which have proved favorable to their native pre- 
decessors. But in the grain-field and fruit-garden the 
case is different. Not only do we bring in species often 
very unlike any aboriginal vegetation and still further 
altered by long cultivation, but we propose an end quite 
different from that for whose accomplishment all the ar- 
rangements of Nature have been made. 
According to the settled order, the whole economy of 
every fully-established plant and animal is directed to 
the production of one more plant or animal to take the 
place of the first one when it perishes. All the excess of 
growth and reproduction is a reward to friends or a trib- 
ute to powerful enemies, intended to make only this one 
end secure. But man is not content with this. He does not 
raise apple-trees for the sake of raising more apple-trees. 
He would cut off all excess not useful to himself, and all 
that is useful he would stimulate to the utmost, and ap- 
propriate to his own benefit. In carrying out this purpose 
he finds himself opposed and harassed at every step by 
rules and customs of the natural world established long 
ages before he was seen upon the earth — laws certainly 
too powerful for him wholly to defy, customs too deeply 
rooted for him to overturn without the most complicated 
consequences. And yet even here, we see that the primi- 
tive order is not an evil, it is simply insufficient. It is 
good as far as it goes, and must be carefully respected in 
its essence, however far it may be modified in detail. We 
find abundant reason for a belief in its usual beneficence 
and for a reluctance to disturb it without urgent necessity. 
At the best the disturbances we must originate will be 
tremendous. Old combinations will necessarily be broken 
up and new ones entered into. As in a country undergo- 
ing a radical change in its form of government, disorders 
will almost certainly break out — some of them fearfully 
destructive and temporarily uncontrollable ; but the gen- 
eral tendency towards a just equilibrium will make itself 
