Chap, xv.] ELECTRICITY AS A CAUSTIC. 167 



to suit the desired purpose, is therefore applied; and the 

 positive may be in the form of a metal plate resting 

 on another part of the body, a moist sponge being 

 interposed. Thus electrolysis has been used for 

 decomposing iiaevi, bronchocele, sebaceous tumour, 

 hydatid cysts, etc. In these cases the negative pole 

 was connected with one or more needles thrust into 

 the tumour, and the positive with a large sponge on 

 another part of the body. One of the chief uses of 

 electricity for electrolysis is for what is called galvano- 

 puncture in the treatment of aneurism. The object is 

 to produce a clot in the aneurismal sac, which by 

 successive additions may finally fill it up. The 

 strength of current used is that obtained from four 

 to eight cells of Stohrer's battery. The electrodes 

 inserted into the sac are of sharp steel needles (being 

 coated to within a short distance of the point with a 

 mixture of shellac and guttapercha), the shafts of 

 which are insulated by gum elastic ; one or more 

 needles maybe connected with the same pole. As re- 

 gards the pole to be used for the sac, the positive seems 

 indicated, since the clot formed on it is small but firm, 

 while that formed round the negative pole is large 

 and soft. Dr. Althaus believes in attaching needles 

 to both poles and inserting both. Dr. McCall 

 Anderson inserts one needle attached to the positive 

 pole, and places a zinc plate and sponge connected 

 with the negative pole on the chest wall, near to the 

 aneurism, the skin being well moistened. The needles 

 having been inserted, the current is passed, first of 

 feeble strength, then slightly increased, and allowed 

 to pass for fifteen to thirty minutes at a sitting. 

 The operation is repeated as indications warrant. 

 Electrolysis has been employed for urinary calcuk, 

 and is extolled as a depilatory. 



(4) For purposes of cautery the elements should 

 be large and the conductors thick. The electrodes 



