ELECTRIC FISH 



goes from one to the other, is closed and, if the dis- 

 charge is sufficiently intense, it can be felt in the hand 

 and arm, even in the shoulder and side. 



A power so strange as this could not fail to give rise 

 to a certain amount of research. In marine biological 

 institutions, the torpedo has become a laboratory case 

 on which considerable study has been, and still continues 

 to be, expended. It is also a favourite exhibit in aqua- 

 riums, because it is easily kept in tanks. So there is no 

 difficulty in getting hold of one to study if we wish to 

 find out what this strange property is, where it resides, 

 and whence it comes. 



There are two organs concerned in producing the 

 electricity which the creature puts forth. They are of 

 similar size, large and symmetrical, and take up the 

 greater part of the two sides of the body. As soon as 

 we have removed the skin in our dissection of the fish, 

 we find them. They are whitish in colour, and each is 

 composed of a mass of little prism-shaped columns 

 lying side by side. These prisms are hexagonal and 

 the appearance of the whole is that of a honeycomb on 

 a small scale. In both cases, mutual compression is 

 responsible for the hexagonal contour, which is the 

 shape best fitted for economy of space. 



If we isolate several of these little columns to find out 

 how they act and how they are made, we discover that 

 they are all alike. They are almost the same size and all 

 reach from the upper to the lower surface of the body. 

 All the prisms have the same structure. Each is made 

 up of very thin disks, superimposed like stacked-up 

 squares, and separated by intervals of a less coherent 

 tissue. This immediately makes us think of a com- 

 parison. Each prism is like a miniature voltaic cell 

 with its successive disks. The whole organ then appears 

 as the equivalent of a group of disk-shaped cells, the 

 elements of which make up for their tiny size by their 

 prodigious quantity. They vary in number according 

 to the size of the fish, but there are several tens of thou- 



J 59 



