96 
DARWINISM 
CHAP. 
been long domesticated in the East, the gold and silver carps; 
and these present great variation, not only of colour but in the 
form and structure of the fins and other external organs. In 
like manner, the only domesticated insects, hive bees and silk¬ 
worm moths, present numbers of remarkable varieties which 
have been produced by the selection of chance variations just 
as in the case of plants and the higher animals. 
Circumstances favourable to Selection by Man. 
It may be supposed, that the systematic selection which 
has been employed for the purpose of improving the races 
of animals or plants useful to man is of comparatively recent 
origin, though some of the different races are known to have 
been in existence in very early times. But Mr. Darwin has 
pointed out, that unconscious selection must have begun to 
produce an e'fect as soon as plants were cultivated or animals 
domesticated by man. It would have been very soon observed 
that animals and plants produced their like, that seed of early 
wheat produced early wheat, that the offspring of very swift 
dogs were also swift, and as every one would try to have a 
good rather than a bad sort this would necessarily lead to the 
slow but steady improvement of all useful plants and animals 
subject to man’s care. Soon there would arise distinct breeds, 
owing to the varying uses to which the animals and plants 
were put. Dogs would be wanted chiefly to hunt one kind 
of game in one part of the country and another kind else¬ 
where ; for one purpose scent would be more important, for 
another swiftness, for another strength and courage, for yet 
another watchfulness and intelligence, and this would soon 
lead to the formation of very distinct races. In the case of 
vegetables and fruits, different varieties would be found to 
succeed best in certain soils and climates ; some might be 
preferred on account of the quantity of food they produced, 
others for their sweetness and tenderness, while others might 
be more useful on account of their ripening at a particular 
season, and thus again distinct varieties would be established. 
An instance of unconscious selection leading to distinct results 
in modern times is afforded by two flocks of Leicester sheep 
which both originated from the same stock, and were then bred 
pure for upwards of fifty years by two gentlemen, Mr. Buckley 
