36 COSMIC FHILOSOPHI, [pt. ii. 



where driven "before it its great congener. In Australia the 

 imported hive-bee is rapidly exterminating the small stmg- 

 less native bee. One species of charlock has been known 

 to supplant another species ; and so in other cases. We can 

 dimly see why the competition should be most severe 

 between allied forms, which fill nearly the same place in 

 the economy of nature ; but probably in no one case could 

 we precisely say why one species has been victorious over 

 another in the great battle of life." ^ 



For our present purpose, however, it is not needful that 

 we should be able to accomplish the latter task, which v/ould 

 require a knowledge of the minutise of the organic world 

 such as is not likely to be possessed by anyone for a long 

 time to come. It is enough for us to note that the ordinary 

 process of competition, among organisms as among dialects, 

 tends to kill out the means much sooner than the extremes. 

 Still more clear will this become, if we recur to one of the 

 hypothetical illustrations given in the preceding chapter. 

 It was there shown that, in the case of a group of ruminants 

 hitherto isolated from carnivorous foes, and in which different 

 strains or varieties have begun to establish themselves, a 

 newly-arriving incident force, in the shape of strong and 

 swift carnivora, will at once tend to exterminate all the 

 intermediate forms, while the extremes will not only be 

 indefinitely preserved, but will become yet more widely 

 different from each other. Now this hypothetical case is 

 probably a fair sample of a very large proportion — perhaps 

 the majority — of the cases in which specific variations have 

 been rapidly accumulated and persistently fixed. It is by 

 no means likely that variation has gone on throughout the 

 oast with a uniform pace ; but there must rather have been 

 immensely long periods of comparative stability, alter- 

 nating with relatively brief periods, during which newly- 

 'ntroduced sets of circumstances have tended to enhance 

 * Origin of Species, 6th edit., p; 6W. 



