CHAP, x.] VARIOUS APPLICATIONS OF ELECTRICITY. 719 



CHAPTER X. 



VARIOUS APPLICATIONS OF ELECTRICITY". 



I. MEDICAL ELECTRICITY. 



HAVE we given the description or even exhausted the list of all the 

 applications of electricity ? Not by a long way ; although we have 

 restricted ourselves to the most important, and those which have 

 been most generally adopted. Our object, it must be remem- 

 bered, was chiefly to place in relief the physico-electric phenomena 

 of various kinds and the laws of their manifestation. 



We cannot however conclude this book without mentioning a 

 certain number of other scientific applications which appear capable of 

 great development, such as the employment of electricity in medicine, 

 and the registering apparatus for continuous meteorological observa- 

 tions. 



It is no part of our business, it will be understood, to estimate 

 the therapeutic or medical value of electricity ; what is incontestable 

 is that this agent produces physiological effects, which for a long 

 time physicians have tried to make use of in medicine. At first the 

 discharges of statical electricity from a Leyden jar were used, but it 

 is chiefly since the discoveries of Galvani and Volta that the action of 

 electric currents has been studied, and that a serious application of 

 them to the treatment of various diseases has been made. 



The electro-medical apparatus are sometimes batteries of a par- 

 ticular construction, sometimes induction coils so arranged in general 

 as to allow of the employment of induced currents of either kind, 

 according to the case of the patient. 



Of these batteries, Pulvermacher's chain is the most frequently 



