FARM ANIMALS. 307 



animals is tlic Slictland pon)-, a ver)- miniature 

 horse in his oriLrinal home, hut orachiallx' in- 

 creasing" in si/e \vlH'n taken to a country of 

 liberal food supply. As an illustration of the 

 effect of climate on animals, one may observe 

 the Gallowav cattle of western Scotland. The\' 

 have developed a remarkably heavy coat of hair 

 because of the cold nnd storm)' weather to 

 which they have been subjected. 



Domesticated cattle receive their food with 

 very little exertion other than that of eating-, 

 while the buffalo of the Western range has been 

 forced to cover considerable territory to find 

 sufficient food. This continuous exercise, along 

 with the severe weather endured, has brought 

 about the lack of thick fleshing quality and the 

 extraordinary constitution of the latter animals. 



3. The causes of Spontaneous or Exti'aordi- 

 nary Wjriation are not well understood. It is 

 known, however, that this t\pe of variation is 

 transmitted onlv very irreoularlv. Selection 

 may be divided into two classes ; namcl}-, natural 

 selection and artificial selection, yet the latter 

 has certain limits put upon it by the former. 



V. Selection. 



By Nat2iral Selection is meant the repro- 

 ducing of aninials most capable of self-protec- 

 tion, of subsisting and again reproducing under 

 existincr conditions. It is what has been called 



