26 LOCALIZED ELECTRIZATION. 



D. — The current of the second helix produces more energetic reflex 

 contractions that that of the first helix. 



This proposition follows from the foregoing experiments, which 

 should be completed in the following manner : — 



Having first equalised the action of the two currents on the 

 sensibility of subcutaneous organs, by holding both moist rheo- 

 phores in the same hand, a rheophore should then be taken in 

 each hand. It will be found that, of currents which act with 

 equal force in producing sensation, that of the second helix will 

 produce contractions which ascend much higher up the arms. 



It is necessary to explain the mode of physiological action in 

 these phenomena. The contractions observed in the upper ex- 

 tremities when a moist rheophore is held in each hand, are mani- 

 fested above the point excited, that is, in a direction contrary to 

 that of the nervous force. They are due to the reaction of the 

 spinal cord, excited by the electric current which passes along 

 the limbs, from the extremities to the centre. I shall return, in 

 Chapter III., § 3, to this mode of electrization, which I have 

 denominated the mode hi/ reflex action. 



E. — When the moist rheojjhores are applied to the surface of the skin, 

 the current of the second helix penetrates the tissues to a greater 

 depth than that of the first. 



I arrived at the above conclusion in the following manner. I 

 had frequent occasion to localize electric excitations in muscles 

 that had lost their contractility and their electric sensibility, 

 consequent upon some injury to their nerves ; as, for instance, to 

 the radial nerve. When I employed the current of the first helix, 

 I Avas able to limit the excitation to the paralysed muscle, even 

 when the strength of the current was considerable. There was 

 neither sensation nor contraction. But, if I replaced the current 

 of the first helix by that of the second, after having equalised the 

 two by taking the two rheophores in each hand, the muscles of 

 the anterior region of the fore -arm would be thruwn into contrac- 

 tion, and the patient experienced sensation. 



It is evident that, in the latter case, the current had penetrated 

 more deeply than in the former, and had been recomposed in the 

 muscles of the anterior region, after traversing the interosseus 

 space. I have seen similar phenomena in the leg, when the 

 internal or external popliteal nerve had been wounded; that is 

 to say, that the current of the second helix excited at once the 

 paralysed and the sound muscles, while that. of the first, apparently 



