io6 The Animal Mind 



hypothesis which we shall discuss in Chapter XI. An 

 unknown force, he concludes, guides the bee in its homing 

 flight (51). Von Buttel-Reepen believes that visual mem- 

 ory will explain all the facts ; that the bees were not dis- 

 turbed by the altered appearance of their hive because 

 they knew their way so thoroughly that nothing could 

 disturb them by the time they had come so nearly home. 

 The visual memory required is, he admits of a peculiar 

 sort, which we shall consider in a later chapter. The odor 

 of the hive does cooperate with vision in certain cases; 

 when a stock of bees has been moved without their knowl- 

 edge, they fly out without making any " orienting flight," 

 as they commonly do on leaving a new place, a fact that 

 is one of the evidences for the visual memory theory. 

 Nevertheless, many of them succeed in finding their way 

 back, and then, if their hive is placed among a number of 

 others, von Buttel-Reepen thinks they " smell" their 

 way back to the right one. He mocks at Bethe's unknown 

 force, on the ground that it must sometimes lead the bee 

 to the hive and sometimes back to the place where food 

 has been found (115). Bethe attempts to answer this by 

 saying that the force acts in cooperation with the physio- 

 logical condition of the animal; the laden bee follows it 

 to the hive, the bee with the empty crop is led back to the 

 food supply (52). Of course one may say what one pleases 

 about the modus operandi of an unknown force without 

 fear of disproof, but also without carrying much conviction. 

 That a mysterious sense of direction exists in the bee 

 is concluded by Bonnier (97) from the following evidence. 

 He first showed that bees whose eyes had been covered 

 by pigmented collodion could go directly to their hive if 

 they were not more than three kilometers away. Smell, 

 however, or muscular memory, might account for this. 



