Modification by Experience 261 



landmarks to guide them (248). Bethe, who thinks bees are 

 guided home neither by vision nor by smell, but by an un- 

 known force to which they respond reflexly, also liberated 

 some bees at sea about 1700-2000 metres from their hive, 

 which was near the foot of Vesuvius and beside some very tall 

 and conspicuous trees. The bees failed to return, yet Bethe 

 thinks, if they were guided by vision, the mountain and the 

 trees should have aided them to do so (32). It may well be, 

 of course, that bees cannot see objects at such a distance. 

 Besides his observation that changing the appearance of a hive 

 did not disturb the bees in their homing flight, Bethe urges 

 against the visual memory hypothesis an observation on a 

 hive which had on one side of it a garden, and on the other 

 side a town, which he thinks the bees never visited, as food 

 was to be had in abundance in the garden. Yet when lib- 

 erated in the town they flew back to the hive with an accuracy 

 certainly not born of their acquaintance with the locality (30). 

 Von Buttel-Reepen, however, doubts whether the bees really 

 never visited the town. Bethe's most striking illustration of 

 his unknown force, however, is derived from his "box-ex- 

 periments." If a number of bees are carried in a box some 

 distance from the hive, on being liberated they fly straight 

 up in the air. Some of them will return to the hive, but if 

 the distance is great enough, many will drop back upon the 

 box. Now if the box has moved only a few centimeters 

 away during the flight of the bees, they will drop back to the 

 precise spot where it was, and take no notice of its new loca- 

 tion. If they were guided by vision, Bethe urges, they could 

 easily see the box (30, 32). This, says von Buttel-Reepen, is 

 arguing that their visual memory must be like ours if it exists 

 at all ; it may be a memory, not of the appearance of the box, 

 but of its locality. He himself, repeating Bethe's experiments, 

 observed the bees on dropping back after their upward flight, 



