Chap, xy.j ELECTRODES FOR MEDICAL PURPOSES. 157 



Fig. 



83. Forms 

 trodes. 



of Elec- 



with a sponge which projects beyond the cup, and is 

 moistened with warm salt water or merely warm water 

 (Fig. 83). The projecting part of the sponge only 

 touches the body, and it may be cut to any shape. 



The cups should be 

 screwed to the handle, so that 

 they may be removed and 

 other forms of rheophores 

 attached to the same handle. 

 Further, the binding screw 

 ought to be at the junction 

 between cup and handle, and 

 not at the end of the handle, 

 as it often is. When the 

 screw is afc the junction, there 

 is no risk of contact being 

 made with, for instance, the 

 hands of the operator. 



Fig. 83 shows some different forms of electrodes ; 

 4 is one of the usual forms ; 1 and 2 are brass knobs 

 covered with wash leather ; 3 is a wire brush on an 

 insulating handle, used for acting on the skin with 

 induction currents ; 5 is for cautery (not used with 

 induction currents ; it is referred to on page 168). 



Similarly, electrodes can be made in any form to 

 suit throat, uterus, rectum, nasal passage, ear, etc. 



MODES OF APPLYING ELECTRICITY. 



First of all it is to be noted that, whatever kind 

 of current is used, the electrodes may be used wet or 

 dry, and the part of the body to which they are 

 applied may be moistened or dried. If moisture is 

 used the resistance of the skin is diminished, and the 

 current may then pass through the skin and reach the 

 moist tissues beneath, which are good conductors. 

 On the other hand, dry skin offers very great re- 

 sistance. Consequently, when it is desired to send 



