366 Darwin, and after Darwin. 



of its generating a sufficient amount of electricity 

 to yield a discharge that can be felt by the hand 

 Nevertheless, that it does discharge under suitable 

 stimulation has been proved by Professor Burdon 

 Sanderson by means of a telephone ; for he found 

 that every time he stimulated the animal its electrical 

 discharge was rendered audible by the telephone. 

 Here, then, the difficulty arises. For of what conceiv- 

 able use is such an organ to its possessor ? We can 

 scarcely suppose that "any aquatic animal is more 

 sensitive to electric shocks than is the human hand ; 

 and even if such were the case, a discharge of so feeble 

 a kind taking place in water would be short-cir- 

 cuited in the immediate vicinity of the skate itself. 

 So there can be no doubt that such weak discharges 

 as the skate is able to deliver must be wholly imper- 

 ceptible alike to prey and to enemies. Yet for the 

 delivery of such discharges there is provided an organ 

 of such high peculiarity and huge complexity, that, 

 regarded as a piece of living mechanism, it deserves to 

 rank as at once the most extremely specialized and 

 the most highly elaborated structure in the whole 

 animal kingdom. Thousands of separately formed 

 elements are ranged in row after row, all electrically 

 insulated one from another, and packed away into the 

 smallest possible space, with the obvious end, or 

 purpose, of conspiring together for the simultaneous 

 delivery of an electric shock. Nevertheless, the shock 

 when delivered is, as we have just seen, too slight to 

 be of any conceivable use to the skate. Therefore it 

 appears impossible to suggest how this astonishing 

 structure much more astonishing, in my opinion, 

 than the human eye or the human hand can ever 



