BOTANICAL EVOLUTION. 367 
destruction of life which goes on among plants? Even such a slow- 
growing tree as an oak, when it reaches maturity, produces its seeds 
by thousands each year, but how few germinate, and how very few 
come to maturity. In any given tract of land where systematic 
planting is not carried on, it is improbable that the average number 
of oaks ever increases. But think what the actual destruction must 
be in such a lowly organized plant as a mushroom, where each spore 
may produce a hundred receptacles, each one scattering its millions 
of spores ;—yet mushrooms are no commoner now than they were 
twenty years ago. 
If now we consider what these figures mean, and what they point 
to, we must surely be prepared to admit that every organism, as soon 
as it comes into existence, enters upon a struggle for bare existence, 
in which the chances of its coming to maturity are—according to its 
kind—many hundreds, or thousands, or even millions to one. Were 
all organized beings sufficiently intelligent to know the probable fate 
which awaited their progeny, then they would wish they had never 
existed. But fortunately for them, the future has no existence, they 
live for the present hour alone. Even among men, the highest of all 
organised beings, it is only an infinitesimal number—in proportion to 
the population of the globe—to whom the truth comes home at all, 
and these, by virtue of their superior intelligence, are generally lifted 
to a great extent out of the operation of the law. The very fact then 
of such a struggle points to another fact, viz., that as all organized 
beings are not equally fitted to take part in this struggle, and as 
in any assemblage of animals or plants of the same kind, some are 
better and some are worse fitted for their part in the battle, then 
those which are not so well fitted as their fellows will probably 
. succumb first, leaving the more perfect individuals to become the 
parents of the next generation. And so we arrive at the pith of, 
the great principle so familiar in name now-a-days—Natural Selection, 
resulting in the survival of the fittest. 
This principle of natural selection has furnished food for 
animated discussion for the last quarter of a century, and though 
held in a somewhat modified form from that in which it was originally 
enunciated by Darwin, the main features of it are now universally 
agreed to. If we take the case of a hundred plants of any one kind, 
we find that some are better fitted than their neighbours for 
sustaining the struggle. Suppose that by virtue of superior adapta- 
tion to the surrounding circumstances, 11) are enabled to survive, 
while the other 90 succumb before reaching maturity; these 10 
become the progenitors of the next generation, which we may again 
suppose to number 100. In this generation the probability is that 
the very properties which enabled the parents to withstand premature 
destruction will be much more strongly developed than in the former 
generation, for—as we have seen—not only is there a tendency 
among all living organisms to vary, but there is also a strong 
tendency to the perpetuation of favourable variations. If of this 
second generation still only 10 survive, then those favourable 
characteristics will be still more intensified in their descendants, and 
so the process will go on—the tendency of natural agencies being: 
always to eliminate the unsuitable examples of every kind, and to 
perpetuate only the suitable. 
