Hillside. 147 



How variable this species appears to be ! Scarcely any 

 two shells are alike, and one might well be forgiven for 

 supposing that the extreme forms belonged to entirely 

 different species. In nature we may safely say that no two 

 specimens of any species are exactly alike, no two plants, 

 no two animals, and so on. The minute differences which 

 we see between human individuals have their representatives 

 among all orders of living beings. Variation is the law of 

 the universe, whilst change and decay are followed by a 

 re-embodiment, and thus advance is made, and progress is 

 maintained. These minute differences will not be observed 

 by a superficial observer, to whom the various individuals 

 of the same species will appear almost exactly' alike ; but to 

 the specialist they become apparent, and enable him to in- 

 dividualise each specimen, and to satisfy himself that vari- 

 ability is indeed the general rule throughout all animate 

 creation. 



Now let us inquire for a moment what man has been able 

 to effect by availing himself of this tendency to variation. 

 Every one is familiar with the marked differences between 

 the various breeds of pigeons, fowls, and rabbits that are 

 kept by fanciers in every part of the country. These breeds 

 appear quite distinct ; there is the carrier pigeon, its ex- 

 cellently developed shape giving it great flying and staying 

 power ; the pouter, in which the throat membrane is de- 

 veloped into an expansive bag in front ; the fantail, with a 

 protuberant thorax and fanlike tail, and many other varie- 

 ties. All of these have undoubtedly been developed, under 

 the selective agency of man, from the common rock pigeon, 

 which lives wild and builds its nest on the rocky parts of 

 our coasts. Very similar and equally marked lines of 



