232 THE WONDER OF LIFE 



at bay ', a very picture of wrath, with its teeth showing 

 and its fur all on end. Some have supposed that the cat 

 makes itself look bigger and that the dog is abashed by 

 the sudden change of dimensions. But the idea that there 

 is deliberate ' bluffing ' cannot be considered, even with 

 a creature as clever as a cat. The cat is angry, and some- 

 times a little afraid ; the raising of the fur is a reflex. 

 What makes the dog shnk off is partly the abruptness of 

 the change of tactics and partly the awareness that this 

 little spitfire ' means business '. 



Now, if ' bluffing ' does not take place in the cat, it is 

 still less likely to occur among the lower animals. There- 

 fore, when we observe the ' terrifying attitude ' of the 

 puss-moth caterpillar, or the Eyed Blenny (Blennius 

 ocellaris), raising and waving its dorsal fin with its curious 

 black ' eye-mark ' when it is attacked, or the Russian 

 tarantula taking a pose which makes it look biggest and 

 most impressive, we must not too hastily conclude that the 

 creatures know what they are doing. What we see is 

 probably an inherited reflex, and is probably of real 

 utility in the struggle for existence, for it does appear to 

 have a disconcerting effect on enemies. 



' Homing '. — It is well known that ants can find their 

 way home from a distance. The present-day interpreta- 

 tion does not postulate any special ' homing instinct ', 

 but regards the phenomenon as due to a combination of 

 factors. There seems no doubt that use may be made of 

 odoriferous substances left on the track, and Bethe 

 started the hypothesis that there is a quantitative or 

 quahtative difference between the scent on the way from 

 the nest and that on the way to the nest. 



The results of Turner's experiments (1907), led him to 



