48 THE DATA OF BIOLOGY. 



connected by a conductor with any point in its transverse 

 section, an electric current is established ; and further, that 

 like results occur when nerves are substituted for muscles. 

 The special causes of these phenomena have not yet beeu 

 determined. Considering that the electric contrasts are most 

 marked where active secretions are going on — considering, 

 too, that while they do not exist between external parts 

 which are similarly related to the vascular currents, they do 

 exist between external parts which are dissimilarly related 

 to the vascular currents — and considering also that they 

 are extremely difficult to detect where there are no appre- 

 ciable movements of fluids ; it may be that they are due 

 simply to the friction of heterogeneous substances, which is 

 universally a cause of electric disturbance. But whatever be 

 the interpretation, the fact remains the same, that there is 

 throughout the living organism, an unceasing production of 

 differences between the electric states of different parts ; and 

 consequently an unceasing restoration of electric equilibrium 

 by the establishment of currents among these parts. 



Besides thess general, and not conspicuous, electrical phe- 

 nomena which appear to be common to all organisms, vegetal 

 as well as animal, there are certain special and strongly 

 marked ones. I refer, of course, to those which have made 

 the Torpedo and the Gymnotiis objects of so much interest. 

 In these creatures we have a genesis of electricity that is not 

 incidental on the performance of their different functions by 

 the different organs ; but one which is itself a function, 

 having an organ appropriate to it. The character of this 

 organ in both these fishes, and its largely-developed con- 

 nexions with the nervous centres, have raised the suspicion, 

 which various experiments have thus far justified, that in it 

 there takes place a transformation of what we call nerve-force 

 into the force known as electricity : this conclusion being 

 more especially supported by the fact, that substances, such as 

 morphia and strychnia, which are known to be powerful 



