THE FARM 305 



ways of peace and for purposes of conquest, would make a 

 most interesting narrative. 



The horse belongs to the vertebrates, or animals with 

 spinal columns, and is in the division known as mammals. 

 To this group belong such domestic animals as cattle, sheep, 

 pigs, dogs, and cats, together with various wild beasts such 

 as bears, wolves, lions, tigers, and elephants. The whale, 

 too, is a mammal and suckles its young, and man himself 

 belongs to the mammals. On the other hand, fish and birds 

 hatch from eggs. 



From studies of the remains of animals found buried in 

 the earth's strata geologists are able to give a detailed story 

 of the ancestry of the horse. This history runs back through 

 geological periods to animals entirely different in appearance 

 from the horse of historic times. This evolution of the horse 

 as it is called is an illustration of the changes that have 

 occurred in plant and animal forms during countless ages. 

 Those forms best adapted to changing conditions have sur- 

 vived. They have perpetuated the characteristics and 

 organs which have best served their needs and have been in 

 most frequent use. Man himself has develope'd and per- 

 fected various breeds of horses, cattle, poultry, and other 

 animals, and a no less wonderful change has been wrought in 

 the kinds and qualities of plant life by selective breeding. 

 The achievements of the last half century in improving plants 

 and animals for man's use and enjoyment has been scarcely 

 less than marvelous. Horticulture, animal husbandry, and 

 general agriculture especially have profited largely by well- 

 directed persistent applications of scientific knowledge in 

 these respects. 



The teeth of the horse in front are powerful incisors in 

 both upper and lower jaws, enabling it to bite off grass rather 

 than pull it off as the cow must do because of lack of the 

 upper incisors. The back teeth of both horse and cow have 



