THAT A HORSEHAIR WHEN PLACED IN A POOL 

 OF WATER TURNS TO A SNAKE 



T would seem that this was formerly a very 

 general article of belief among the country 

 people of Great Britain and Ireland. Even 

 Shakespeare seems to have accepted the current 



notion, for in " Antony and Cleopatra" (Act I, Scene 2, 



line 200) we find the following: 



Much is breeding, 



Which, like the courser's hair, hath yet but life 

 And not a serpent's poison. 



Even Sir Thomas Browne in his elaborate work on the 

 "Vulgar Errors" of his time ( u Pseudodoxia Epidemica") 

 does not allude to this error in natural history, though we 

 can scarcely believe that he was not familiar with the cur- 

 rent notions on the subject, and therefore we are led to sus- 

 pect that he accepted the popular view as being correct. 



The error arose out of two very interesting facts. In 

 the first place there is a species of threadworm (the Gor- 

 dius aquaticus) which at one stage of its existence is para- 

 sitic but which develops in stagnant pools and so closely 

 resembles an animated horsehair that it gave rise to the 

 idea that it was really a horsehair which had fallen into 

 the water and had become alive. 



The other fact was that when a dry horsehair is placed 

 in water it frequently moves, just as a thin shaving of wood 

 will curl and move when laid on a damp surface or as the 



