INDUCED ELECTRICITY. 33 



the other, without ever disorganizing the skin, or leaving any 

 trace behind further than a slight erythema or a little elevation 

 of the papillfe. It is evident that such an agent will fulfil a 

 number of indications ; whether we wish to excite the sensibility 

 of the skin, as in cases of cutaneous anaesthesia ; or whether we 

 wish to produce some revulsive local action, as in neuralgic and 

 rheumatic pains. This cutaneous excitation may be repeated 

 frequently, and may be applied to all points of the surface, even 

 of the face, since it leaves no mark behind ; and it may be con- 

 trolled in accordance with the excitability of every patient, or of 

 any region of the body. 



There is often need for an intense current in the treatment of 

 certain muscular affections. In such cases, only induced elec- 

 tricity is applicable ; since it does not exert the calorific action of 

 contact electricity. 



The chemical or electrolytic action of induced electricity is so 

 feeble, that it is useless as a means of coagulating the blood, in 

 the treatment of aneurisms. Induction instruments will, however, 

 even when of small size, exert a considerable influence upon con- 

 tractility, and this greatly facilitates their employment. 



A. — The different physiological actions of the induced currents of 

 the first and of the second helix cannot he ap-plied indifferently in 

 practice. 



The two induced currents (of the first and of the second helix) 

 the physiological properties of which are so dissimilar, should 

 exert a different therapeutic action, answering, for each of them, 

 to some special indications. Although empirical trial has often 

 played a principal part in therapeutics, we should nevertheless be 

 guided in such empiricism by the physiological action of medicinal 

 agents. The path that I have followed, in the therapeutical use 

 of the currents of the two helices, has been that which was traced 

 out for me by physiological experiment. If, however, the phy- 

 siological differences between the currents had been scarcely 

 sensible, I should in that case have drawn from them no thera- 

 peutical deductions ; in order not to complicate unnecessarily the 

 art of medical electricity, which, as we shall see, is sufficiently 

 difficult already. There must be something more than slight 

 varieties between these physiological properties. I may say, 

 without exaggeration, as regards their effect on the cutaneous 

 sensibility, that they differ as water that is warm differs from water 

 that is boiling, or as iron slightly warm differs from iron that is 

 white-hot. 



We do not, indeed, find so great a difference between the two 



u 



