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, ete.— 
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, 
