PECULIAR SECRETIONS. 373 



in a slip of tinfoil fixed on sealing wax. The animal is 

 capable of giving its shocks in the air, as well as in its na- 

 tural element the water. Those given in the former are 

 even much stronger than in the latter, owing probably to 

 the fluid being more confined by the surrounding medium. 

 The shock iar given with the same degree of force, even 

 when the animal is insulated, and the person receiving it 

 likewise insulated. In such circumstances, fifty shocks 

 have been received in the space of a minute and a half. 

 The most powerful effect is produced by these organs, 

 when the circuit is made between their upper and under 

 surfaces, as these appear to be in opposite states of electri- 

 city. 



The history of animal electricity received some valuable 

 additions from the experiments of Dr WILLIAMSON in Phi- 

 ladelphia *, on the Gymnotus. He found that this animal 

 could communicate its shock to the hand, in water, even 

 when held at the distance of three feet. It killed small fish 

 by the shock, without coming into actual contact, and stun- 

 ned larger ones in the same manner. 



In both these fishes, the electrical energy is insufficient to 

 produce appearances of attraction and repulsion in the most 

 delicate electrometers, although feeble sparks have been 

 perceived by different observers, in consequence of using 

 the utmost precaution in interrupting the circuit. The ani- 

 mal has the power of making the discharge from any part 

 of the surface of its peculiar organ, or from the whole, at 

 pleasure ; but it is incapable of communicating shocks for 

 any length of time, without exhibiting unequivocal symp- 

 toms of fatigue. If the electrical energies of the fish are 

 too much excited, it becomes debilitated, and expires. 



Phil, Trans. 1775, p. 94. 



