THE STUGGLE FOR LIFE. Iq I 
It is a matter of common experience that no two individuals 
are born exactly alike in every respect. The resemblance of 
two Dromios makes a capital foundation for “A Comedy of 
Errors,” but the impression of their dirty thumbs on a piece 
of white paper would in itself suffice to show their non-identity. 
Moreover, every individual, from the law of its organization 
in other words, from heredity, tends to vary in certain definite 
directions, 
No one would expect that the variations of the cat, would tend 
to produce the horn of a rhinoceros, or the whale to develop 
legs like those of a horse. In Nature, we find that the varia- 
tions seen at any given time are small in themselves, but that 
some of them confer advantage, while others handicap their 
possessors, in their struggle for life. For instance, a small 
difference in the length of the leg in a beast of prey will affect 
its ability to procure food, and a small advantage will greatly 
increase the probability of the favoured individual reaching 
maturity and leaving offspring behind it. 
There is also another well known law of Nature, which is 
this, that the offspring are likely to resemble the parents, 
therefore those individuals, either naturally or artificially se- 
lected to continue the race by the possession of any peculiarity, 
will leave offspring more or less resembling themselves; the 
Same cause will act in the next generation, and so on, until in 
process of time, the originally small advantage is increased by 
the accumulation of individually very small Variations, until 
a descendant is produced strikingly superior to its ancestor in 
its ability either to Procure its food, or to avoid its enemies, 
This is proved by the facts of what is called “artificial se. 
lection.” It is in the power of man to influence the characters 
of his domestic animals, and by selecting the parents to 
Procure breeds varying in any desired direction, J] may 
illustrate this by reference to the case of the domestic pigeon, 
in which it is well known that races may be developed which 
will breed almost true among themselves even to the colour 
