INSTINCTIVE, EMOTIONAL AND REFLEX ACTION 32J 



then went to the house to get her own supper and re- 

 turned to them. She had evidently discovered their dis- 

 appearance on going to the house, and took this course 

 to save them. 



"A man once desired to test his dog, which was lying 

 down quietly sleeping. In the midst of a general conver- 

 sation, he inserted the words, 'The cow is in the potatoes.' 

 The dog jumped up at once, dashed out to the garden and 

 appeared surprised at not finding the cow there. 



"Another dog had for some time chased a rabbit, which 

 ran in a circular course to a burrow and escaped the dog. 

 Finally the dog, on starting another rabbit, ran indirectly 

 across the circle to the mouth of the burrow and awaited 

 the rabbit there. 



"It is well known that some ants keep a certain species 

 of insects called aphides. These stand in precisely the 

 same relation to ants that cows do to human beings. The 

 aphides are regularly milked by the ants and a sweet nu- 

 tritious liquid somewhat resembling honey is thus se- 

 cured. The ants sometimes build stables for their cows, 

 allowing them to pasture on certain plants in such a way 

 that the cows cannot escape. Naturalists have repeatedly 

 seen ants milk their cows. 



"Three species of ants keep other ants as slaves. The 

 slaves tend the aphides, milk them, and often climb trees 

 and plants in order to find male aphides to increase the 

 dairy. The slaves even put the food into the mouths of 

 their masters. Bugs are also enslaved by ants and made 

 to carry heavy burdens. 



"Ants have been seen to make a bridge across a small 

 vessel of water, using pieces of wood and straw. The 

 ants might have brought earth for this bridge, but they 

 illustrated the choice of means to ends, and used instead 

 pieces of wood and straw. 



