MEDICAL BATTERIES. 



73 



Fig. 28. 



sistance tlian wet sponge to the faradic current. The difference 

 is due to the different thickness of the two bad conductors that 

 have to be traversed by 



a current directed upon 

 the surface of the body 

 Therefore, in certain cir- 

 cumstances, I prefer th^ 



metallic rheophores of large surface (fig. 26), 

 also covered with wet leather, to the moist 

 sponges ; because the former practically increase 

 the power of the current. The large metallic 

 rheophores have also the advantage that they 

 may be more or less pressed upon the skin, 

 without annoying the patient, as in the case 

 of the sponges, by water being freely squeezed 

 out from them. 



IV. — Indirect muscular faradization. 



Indirect muscular faradization requires, as 

 may be supposed, an exact knowledge of the 

 positions and the anatomical relations of the 

 nerves. It is most practicable in the limbs, 

 where most of the nervous trunks, subcutaneous 

 at some point of their length, are accessible 

 to rheophores. 



In the upper limbs, electrical action can be precisely limited to 

 the median nerve, at the inner side of the lower third of the arm, and 

 to the ulnar, at its passage along the channel which separates the 

 inner cordyle from the olecranon. Faradization of the radial may 

 be practised at the outer side of the humerus, at the junction of its 

 middle and lower thirds, where the nerve escapes from the humeral 

 channel. It would be impossible not to stimulate directly, at the 

 same time, some fibres of the triceps and brachialis muscles. The 

 musculo-cutaneous nerve may be faradized in the axilla. It is 

 also possible to localize the electric action in some terminal 

 branches ; for example, in those that supply the muscles of the 

 thenar eminence, and in the collateral nerves. 



In the lower limbs indirect muscular faradization is still more 

 simple. The crural nerve is found in the fold of the groin, 

 external to the femoral artery ; and the popliteal nerves in the 

 popliteal space. It sliould be known that electricity will not reach 

 the internal popliteal nerve, which is protected by a great thick- 

 ness of cellular tissue, unless the current be somewhat powerful. 



F.g. 



Fig. 27. — Olivary metallic 

 rheopliore. 



Fig. 26. — Conical metallic 

 rbeophore. 



