V 
NATURAL SELECTION 
123 
observe or think of, goes on also among the millions and 
scores of millions of individuals which are comprised in almost 
every species; and must get rid of the idea that chance 
determines which shall live and which die. For, although in 
many individual cases death may be due to chance rather 
than to any inferiority in those which die first, yet we cannot 
possibly believe that this can be the case on the large scale 
on which nature works. A plant, for instance, cannot be in¬ 
creased unless there are suitable vacant places its seeds can 
grow in, or stations where it can overcome other less vigorous 
and healthy plants. The seeds of all plants, by their varied 
modes of dispersal, may be said to be seeking out such places 
in which to grow; and we cannot doubt that, in the long run, 
those individuals whose seeds are the most numerous, have the 
greatest powers of dispersal, and the greatest vigour of growth, 
will leave more descendants than the individuals of the same 
species which are inferior in all these respects, although now 
and then some seed of an inferior individual may chance to be 
carried to a spot where it can grow and survive. The same 
rule will apply to every period of life and to every danger to 
which plants or animals are exposed. The best organised, or 
the most healthy, or the most active, or the best protected, or 
the most intelligent, will inevitably, in the long run, gain an 
advantage over those which are inferior in these qualities; 
that is, the fittest will survive, the fittest being, in each particular 
case, those which are superior in the special qualities on 
which safety depends. At one period of life, or to escape one 
kind of danger, concealment may be necessary ; at another 
time, to escape another danger, swiftness; at another, intel¬ 
ligence or cunning; at another, the power to endure rain or 
cold or hunger; and those which possess all these faculties in 
the fullest perfection will generally survive. 
Having fully grasped these facts in all their fulness and 
in their endless and complex results, we have next to consider 
the phenomena of variation, discussed in the third and fourth 
chapters ; and it is here that perhaps the greatest difficulty will 
be felt in appreciating the full importance of the evidence as set 
forth. It has been so generally the practice to speak of 
variation as something exceptional and comparatively rare — as 
an abnormal deviation from the uniformity and stability of the 
