INTRODUCTORY. zs 
Nor is this all, for the change which he has brought 
about in the natural balance is as the ripple caused 
by a heavy stone falling into a pool, which extends 
itself in an ever-increasing degree until the banks 
themselves are reached. No one circle, so to speak, 
of nature is complete in itself, but each forms a link 
in an endless and endlessly-interwoven chain, whereof 
every part is more or less intimately connected with 
every other. 
And thus man’s catalogue of enemies and friends 
is practically limited only by the bounds of creation. 
There is a first, or inmost circle, if we may use the 
expression, composed of directly and appreciably 
hostile beings. Each of these beings has its own 
circles respectively of friends and foes, which, mwd¢atzs 
mutandis, must therefore be inversely ranked as the 
foes and friends of man in a secondary degree—foes 
and friends once removed. ‘These, in their turn, 
have their own friends and foes, which again exert 
an indirect but unquestionable influence upon man ; 
and so in an ever-widening circle, which grows in 
complexity as it increases in size. 
So with man’s friends. Animals which render the 
world more fit for his habitation; which help him to 
till the soil and force it to bear its increase; which 
prosecute an unfailing campaign against others which 
injure him; which by their superior strength, aided 
and directed by his intellect, supplement his labours 
by their own: all these are his friends, and in their 
turn are objects of friendship or hostility to circle 
after circle of beings more or less closely connected 
