THE SERPENT’S TONGUE 143 
already been intimated, an incidental use of the 
tongue, probably confined, or at all events most 
advantageous to the vipers and to other venomous 
serpents of lethargic habits. In the case of the 
extremely active, non-venomous snake, that glides 
away into hiding on the slightest alarm, the tongue 
would be of little use or no value as a warning organ. 
Between a snake of this kind and the slumberous 
pit-viper the difference in habit is extreme. But 
at bottom, all ground snakes are alike in disposi- 
tion—all hate to be disturbed, and move only 
when necessity drives; and we can imagine that 
when the tremendous weapon of a lethal tooth had 
been acquired, when experience began to teach the 
larger mammalians to view the serpentine form 
with suspicion and to avoid it, the use of the 
tongue as a warning would react on the serpent, 
making it more and more lethargic in habit—as 
inactive, in fact, as every snake loves to be. 
There is, I imagine, another and more important 
use of the tongue, older than its warning use, 
although this may date back in time to the Miocene 
period, when the viperine form existed—a use of 
the tongue common to all ophidians that possess 
the habit of exserting and vibrating that organ 
when excited. The subject is somewhat com- 
plicated, for we have not only to consider the 
tongue, but the whole creature of which the tongue 
is so small a part; its singularity and anomalous 
position in nature, and the many and diverse ways 
in which the animals it preys on are affected by 
