THE WAY OF ‘THE WILD 53 
always on, and its complications are so many and s0 intricate 
and its consequences so profound that a little space is well de- 
voted to its analysis. 
Selective effect of natural conditions. There is a blind but 
wholesale struggle of living things against what may be called 
natural conditions, which assert their influence independent of 
struggle against competition with other living beings, and gen- 
erally before it begins. 
First of all are climatic and seasonal influences. Hosts of 
young things, both plant and animal, come into existence only 
to perish on the spot from adverse climatic influences. Many 
species exist, in northern latitudes for example, only by the 
narrowest margin, and one exceptionally hard winter will close 
them out by the millions. In this way whole fields of wheat 
and clover are “winter killed,” as we say, and whole forests 
die after an exceptionally dry summer followed by an unusually 
severe winter. 
A sudden freshet may wash away in immense numbers the 
season’s crop of seeds of maple, elm, or oak, and send them 
downstream to rot in the lowlands. The same freshet may kill 
a valuable lot of mature timber downstream and change forever 
the flora of the locality. - 
A wet summer may drown most of the bumblebees, and then 
the farmers need have small expectation as to the crop of clover 
seed, which is dependent upon bees for fertilization. 
A late fall may so stimulate growth in peach trees and other 
tender plants as to prevent that “ripening” of the wood neces- 
sary to a successful endurance of extreme cold. On the other 
hand, a “warm spell’ in winter may start the buds, after which 
a “cold snap” will kill outright in a day the prospective crop 
of the year. The apple crop is occasionally lost by late cold 
weather after ‘‘setting”’ of the young fruit. Of course this 
1When the Chicago drainage canal was dug, many bodies of timber along 
the banks of the Illinois were killed by the new water level established, and 
many damage suits resulted. 
