Chap. III. 
STRUGGLE FOR EXISTENCE. 
77 
but probably in no one case could we precisely say wliy 
one species has been victorious over another in the 
great battle of life. 
A corollary of the highest importance may be deduced 
from the foregoing remarks, namely, that the structure 
of every organic being is related, in the most essential 
yet often hidden manner, to that of all other organic 
beings, with which it comes into competition for food or 
residence, or from which it has to escape, or on which it 
preys. This is obvious in the structure of the teeth and 
talons of the tiger; and in that of the legs and claws of 
the parasite which clings to the hair on the tiger’s body. 
But in the beautifully plumed seed of the dandelion, 
and in the flattened and fringed legs of the water-beetle, 
the relation seems at first confined to the elements of 
air and water. Yet the advantage of plumed seeds no 
doubt stands in the closest relation to the land being 
already thickly clothed by other plants; so that the 
seeds may be widely distributed and fall on unoc¬ 
cupied ground. In the water-beetle, the structure of 
its legs, so well adapted for diving, allows it to 
compete with other aquatic insects, to hunt for 
its own prey, and to escape serving as prey to other 
animals. 
The store of nutriment laid up within the seeds of 
many plants seems at first sight to have no sort of 
relation to other plants. But from the strong growth 
of young plants produced from such seeds (as peas 
and beans), when sown in the midst of long grass, 
I suspect that the chief use of the nutriment in the 
seed is to favour the growth of the young seedling, 
whilst struggling with other plants growing vigorously 
all around. 
Look at a plant in the midst of its range, why does 
it not double or quadruple its numbers ? We know 
