SNAKE AND FROG PRATTLE 239 



there is evidence in support of the view that one species 

 has a membranous eyelid similar to, but slighter than, 

 that of a bird. It is not to be doubted that another 

 reptile — the green turtle — is thus endowed, and that 

 the "winking membrane" is found in many animals 

 at the inner angle or beneath the lower lid of the eye. 

 This membrane is represented in animals by a rudiment 

 only. In the eyes of human beings the small reddish 

 patch in the corner corresponds to the winking mem- 

 brane — indeed, is the vestige of it. In monkeys, and 

 in most mammals below them, there is present in this 

 vestige a small piece of cartilage, and this is found 

 occasionally in man. In white races it is very rare, 

 occurring, as far as observations have shown, in less 

 than one per cent. Recent investigations by Dr. Paul 

 Bartels show that in twenty-five South African natives 

 whom he had examined it occurred in twelve. Another 

 investigation found it five times in twenty-five Japanese. 

 It is curious to find that vestige more common in 

 certain races, as it shows that in this small point they 

 are less advanced than the white race. 



This quotation from a forgotten source supplies 

 important links in the chain of evidence in favour of 

 the theory that certain species of snakes may have 

 the winking muscle, which exists in marine reptiles 

 and is present in some human beings. Apart from 

 theory, it has been my good-fortune to see a sleeping 

 snake the eyes of which were obscured by a greyish 

 film, giving it the appearance of being "wall-eyed." 

 Being satisfied that it was blind, for it betrayed no 

 uneasiness at a threatening demonstration, a deter- 

 mination was made to preserve it for critical examina- 

 tion. As soon as the snake was touched the cloudy 

 veils were withdrawn, and the eyes flashed with the 

 fire of malignity. It appeared to be spiteful because 



