372 PHILOSOPHY OF ZOOLOGY. 



this benumbing effort many times in succession in the water, 

 as well as in the air, when arrived at maturity, and even pre- 

 vious to the natural period of exclusion from the uterus of 

 the mother. When caught in the net, it gives a shock to the 

 hands of the incautious fisherman who ventures to seize it. 

 When concealed in the mud, it is capable of making its 

 most violent efforts ; and is able to benumb the limbs to 

 such a degree, as to throw down the passenger who inad- 

 vertently places his foot upon the body. 



Although the benumbing powers of the torpedo were 

 known to PLATO and ARISTOTLE, and had frequently been 

 proclaimed by the verses of the poet, and the exaggerated 

 statements of the fishermen, it was not until the doctrines of 

 electricity had been established, that the circumstances un- 

 der which these were exerted, and the effects which they 

 produced, were investigated with any degree of success. 

 The first person who turned his attention particularly to 

 this subject, was Mr WALSH, and he succeeded in demon- 

 strating, that the animal could exert its benumbing power 

 at pleasure, and that the shock was regulated by all those 

 circumstances which influence the discharge of the electric 

 fluid from the Leyden phial ; in other words, he established 

 the identity between the electric fluid and the benumbing 

 power. His experiments were communicated to the Royal 

 Society, July 1. 1773 *. According to the experiments of 

 this observer, the shock of the torpedo is prevented by all 

 electrical non-conductors, as glass or sealing-wax ; while it 

 readily passes along brass-wire, water, or persons whose 

 hands are joined. The torpedinal fluid was unable to force 

 itself across the minutest tract of air, or from one link of 

 a small chain, suspended freely to another ; or through an 

 almost invisible separation, made by the edge of a penknife 



* Phil. Trans. 1773, p. 461. 



