%, 



^Ofc 





Chap. XXVIII. 



CONCLUDING REMAEKS. 



413 



$P 



diversified conditions of life, to avoid enemies of all kinds, and 

 to struggle against a host of competitors. Hence, under 'such 

 complex conditions, it would often happen that modifications 

 of the most varied kinds, in important as well as in unimportant 

 parts, would be advantageous or even necessary ; and they would 

 slowly but surely be acquired through the survival of the fittest. 

 Various indirect modifications would likewise arise through the 

 law of correlated variation. 



Domestic breeds often have an abnormal or semi-monstrous 

 character, as the Italian greyhound, bulldog, Blenheim spaniel, 

 and bloodhound amongst dogs,— some breeds of cattle and pigs^ 

 several breeds of the fowl, and the chief breeds of the pigeon! 

 The differences between such abnormal breeds occur in parts 

 which in closely-allied natural species differ but slightly or not 

 at all. This may be accounted for by man's often selecting, 

 especially at first, conspicuous and semi-monstrous deviations of 

 structure. We should, however, be cautious in deciding what 

 deviations ought to be called monstrous : there can hardly be a 

 doubt that, if the brush of horse-like hair on the breast of the 

 turkey-cock had first appeared on the domesticated bird, it would 

 have been considered a monstrosity; the great plume of feathers 

 on the head of the Polish cock has been thus designated, though 

 plumes are common with many kinds of birds ; we might call 

 the wattle or corrugated skin round the base of the beak of the 

 English carrier-pigeon a monstrosity, but we do not thus speak 

 of the globular fleshy excrescence at the base of the beak of 

 the male Garpophaga oeeanica. 



Some authors have drawn a wide distinction between 

 artificial and natural breeds; although in extreme cases the 

 distinction is plain, in many other cases an arbitrary line 

 has to be drawn. The difference depends chiefly on the kind 

 of selection which has been applied. Artificial breeds are 

 those which have been intentionally improved by man ; they 

 frequently have an unnatural appearance, and are especially 

 liable to loss of excellence through reversion and continued 

 variability. The so-called natural breeds, on the other hand, 

 are those which are now found in semi-civilised countries, and 

 which formerly inhabited separate districts in nearly all the 

 European kingdoms. They have been rarely acted on by man's 



