146 PRIMEVAL MAN. 



they desire to produce, or are capable of 

 producing, are effected directly by the use 

 of those organs under the guidance of 

 implanted instincts. There are some very 

 curious cases among the lower animals of a 

 near approach to the principle involved in 

 the use of tools — that is to say, the use of 

 natural force through artificial means. Thus 

 the common Grey or Hooded Crow is con- 

 stantly in the habit of lifting shell-fish to a 

 certain height in the air, and then letting 

 them fall upon the rocks of the shore, in 

 order to break the shells. Some species of 

 Monkey will even use any stone which may 

 be at hand for the purpose of striking and 

 breaking a nut. The Elephant tears branches 

 from the trees and uses them as an artificial 



