CHAP, vii THE INDUSTRIES OF ANIMALS 137 



proved that they build up a visual knowledge of the 

 country around the hive. They are quite nonplussed 

 when taken out a couple of miles on to a lake near the 

 hive and liberated on the featureless water. In the case 

 of ants the trend of investigation is against the hypothesis 

 of any mysterious sense of direction. The little people 

 seem to build up a working knowledge of their district, 

 utilising various kinds of imprints or memories in finding 

 their way home. Experiments show r that they utilise 

 hints derived from scents, the direction of the light, 

 illumination of wayside objects, the turns and slopes 

 of the road, and so on. Orientation is the outcome of a 

 series of recognitions, differing for different kinds of 

 animals ; the recognitions depend on a previous regis- 

 tration of imprints ; and the registration implies an 

 hereditary sensitiveness exquisitely specialised. 



