CREATURES OF MYSTERY 
69 
may be accomplished by a variety of means, provided the sub¬ 
ject can concentrate his thinking on a given theme to the ex¬ 
clusion of everything else, and at the same time relax com¬ 
pletely. This is known as hypnotic sleep, when the subject may 
be controlled at will and is completely within the power of the 
one doing the hypnotizing. 
This art is unquestionably employed by certain species of 
reptiles in acquiring their food. Such art is ordinarily referred 
to by lay observers as “charming,” and is resorted to by rattle¬ 
snakes and perhaps other serpents as a means of procuring 
their food supply, such as birds, rodents, and other small game. 
