SIGHT — FIELDVVORK AND EXPERIMENTS 53 



ment of a slug or worm will attract the Slow Worm which, 

 having tested the prey with its tongue, will seize it and eat it. 



Slow Worms, being easy to find and keep in a vivarium, 

 are good subjects for study, and though their speed of seizing 

 prey cannot be compared with other lizards, they can be 

 shown to have considerable acuity of vision. I have proved 

 that a Slow Worm can see the wriggling of a worm at a 

 distance of nearly three feet, while the slightest movement 

 of even the "horns" of a slug will be detected from twelve 

 inches away. 



Snakes have been subjected to much faulty observation 

 and are spoken about with fluent ignorance by those who 

 have learned their snake-lore from country-folk. It is true 

 that their senses are not easy to assess without close observa- 

 tion, and it is easy to fall into error if the tales of uninformed 

 travellers abroad are taken as a basis of information. The age- 

 old stories about snake-charmers are the root of many quite 

 inaccurate views on the behaviour of snakes, and it is some- 

 what amusing to reflect that the music of the "charmer's" 

 pipe is said to be the reason for his power over snakes when 

 in fact it is the eyesight of the snake that makes it respond to 

 the charmer's actions. What happens is that the charmer sits 

 on the ground with his pipe while a cobra is a yard or two 

 away from him. He plays his pipe and sways to the oriental 

 rhythm of his music. Soon the cobra lifts the front part of 

 its body, extends its hood and appears to make side-to-side 

 movements as if following the plaintive notes from the pipe. 

 In reality it is the sight of the moving pipe that stimulates the 

 snake into action. It will be noted by any acute observer 

 that the snake is never more than a few feet away from the 

 charmer, and thus it is enabled to see the man and his pipe 

 as they sway to and fro. If it were truly the sound of the 

 music that influenced the cobra, there is no reason why it 

 could not be a considerable distance from the charmer, but 

 he is unlikely to risk losing his snake in order to satisfy the 

 scientific curiosity of one member of his audience. 



Snakes on the whole are short-sighted, and they would 

 have little use for long sight since they are often in under- 

 growth and normally could hardly be closer to the ground. 

 Prey is trailed by scent ; and further reference to this will be 



