148 SNAKES. 



through a narrow sHt. A true ' hiss,' such as we produce 

 with closed teeth in prolonging the sound of s, a serpent 

 can never express. The nearest approach to it in the 

 human voice is when the tongue is in the position as if 

 we are about to say ye or he, and then prolong the breath ; 

 that is to say, breathe out while the tongue is so placed 

 before the word is uttered. 



Naturally the larger the snake the stronger the ' hiss ; ' 

 the more rapid the expiration, the more powerful will be 

 the volume of air with its attendant soufflejnent. 



The sound and action, as well as degree, are easily seen 

 in the 'puff adder' {Clotho,ov Vipera arietans). When angry 

 or alarmed, it draws in a full breath, and its body swells 

 perceptibly ; then you hear the escaping air like a prolonged 

 sigh or blowing till the lungs are empty. This process is 

 repeated as long as the provocation lasts. 



These alternate inspirations and expirations, with their 

 accompanying movements, the swelling and then diminishing 

 of the trunk and the regular soiLfflants, are so precisely like 

 those of a pair of bellows, that excepting in shape, we require 

 no more complete comparison. The degree or strength of 

 hiss is in this reptile very perceptible. When recently 

 imported and easily excited, its violent ' puffing ' corresponds 

 with a very large pair of bellows ; but in time it grows less 

 alarmed at the appearance of the human beings who un- 

 ceremoniously stare at it ; and at length the puffing is very 

 slight, ceasing altogether after the snake becomes accus- 

 tomed to its surroundings. But if molested and alarmed, 

 you then see the full play of the lungs, and the whole body 

 alternately expanding and contracting as before. 



