52 MENTAL EVOLUTION IN MAN. 



water-currents, which induce the animals to make allowance 

 for the force of the current by running in the opposite direction 

 to its flow before entering the water. Dogs accustomed to 

 tidal rivers, or to swimming in the sea, acquire a still further 

 generic idea of uncertainty as to the direction of the flow at any 

 given time ; and therefore some of the more intelligent of these 

 dogs first ascertain the direction in which the tide is running 

 by placing their fore-paws in the stream, and then proceed to 

 make their allowance for drift-way accordingly. * 



Lastly, Mr. Darwin writes : — " When I say to my terrier 

 in an eager voice (and I have made the trial many times), ' Hi, 

 hi, where is it?' she at once takes it as a sign that something 

 is to be hunted, and generally first looks quickly all around, 

 and then rushes into the nearest thicket, to scout for any 

 game, but finding nothing, she looks up into any neighbouring 

 tree for a squirrel. Now, do not these actions clearly show 

 that she had in her mind a general idea, or concept, that some 

 animal is to be discovered and hunted ? " f 



From the many instances which I have already given in 

 Animal Intelligence of the high receptual capabilities of ants, 

 it will here be sufficient to re-state the following, which is 

 quoted from Mr. Belt, whose competency as an observer no 

 one can dispute. 



" A nest was made near one of our tramways, and to get 

 to the trees the ants had to cross the rails, over which the 

 waggons were continually passing and re-passing. Every 

 time they came along a number of ants were crushed to 

 death. They persevered in crossing for some time, but at 

 last set to work and tunnelled underneath each rail. One 

 day, when the waggons were not running, I stopped up the 

 tunnels with stones ; but although great numbers carrying 

 leaves were thus cut off from the nest, they would not cross the 

 rails, but set to work making fresh tunnels underneath them." 



* See Animal Intelligence, pp. 465, 466. 



t Of course the words "general idea " and "concept " here are open to that 

 psychological objection for the avoidance of which I have coined the terms generic 

 idea and recept. 



