THE SERPENT'S TONGUE 141 



habits has more ways than one of making itself 

 conspicuous to and warning off any large heavy 

 animal that might injure by passing over and 

 treading on it ; and I think that in ophidians of 

 this temper the tongue has become, incidentally, 

 a warning organ. Small as it is, its obtrusion is 

 the first of a series of warning motions, and may 

 therefore be considered advantageous to the animal ; 

 and, in spite of its smallness, I believe that in very 

 many instances it accomplishes its purpose with- 

 out the aid of those larger and violent movements 

 and actions resorted to when the danger becomes 

 pressing. 



All large animals, including man, when walking 

 on an open space, see the ground before them, with 

 every object on it, even when the head is raised 

 and when the animal's attention is principally 

 directed to something in the distance. The motions 

 of the legs, the exact measurement of every slight 

 obstruction and object in the way — hillocks, de- 

 pressions in the soil, stones, pebbles, sticks, etc. — 

 are almost automatic ; the puma may have nothing 

 but his far-seen quarry in his mind, and the philo- 

 sopher be thinking only of the stars, as they move, 

 both quite unconscious of what their feet are doing ; 

 but the ground must be seen all the same, otherwise 

 they could not go smoothly even over a compara- 

 tively smooth surface. 



When the man or other animal progressing in 

 this ordinary way comes to where a serpent, with 

 a protective or assimilative colour and appearance, 



