92 The Animal Mind 



faintness of the recently established path as compared with 

 the old one (426). Bethe observed also that if a strip of paper 

 had been adopted into an ant road, and was then while an 

 ant was on it rotated through 180 degrees, the ant stopped 

 and was disturbed on coming to the end of it (30). Experi- 

 ments on rotating ants were made also by Lubbock (248), 

 and seem to give puzzling and conflicting results; it is not 

 clear why even on the assumption that there is a difference 

 in odor between the road to the nest and that from the nest, 

 an ant on a road which led both ways should have found her 

 course interrupted by rotation. One fact, Bethe thinks, 

 shows that even assuming two road smells is not enough. 

 Ants of certain families (Lasius) which habitually make regu- 

 lar and frequented roads, can if they come upon one of these 

 roads in wandering at once take the proper direction, either 

 to or from the nest. Evidently the mere presence of two 

 smells would not enable them to do this. Bethe suggests 

 that the particles of the two chemical substances are also 

 differently polarized, so that one of them can be followed only 

 in one direction, the other in the opposite direction (30). 

 Wasmann objects to this that an ant returning on its own traces 

 would destroy them, as the opposite polarizations would can- 

 cel; and that similar confusion would occur on a narrow 

 and much frequented road (426). He and Forel (132) both 

 think that, granting the distinction between the outward 

 and inward paths, which is made by only a few families of 

 ants, the direction is most probably given by a perception of 

 the "smell form" of the footsteps obtained through the 

 antennae. 



Recently C. H. Turner has come to the conclusion that ants 

 are not guided " slavishly" or reflexly by the odor of their 

 tracks in finding the way to and from the nest. He made 

 a small cardboard stage from which an inclined cardboard 



