DIRECT APPLICATION OP IONS 109 



" As the cations go down the electric current and 

 the anions go up, so under the anode the cations 

 will penetrate through the skin, while the anions 

 will penetrate under the cathode."* This is a 

 regular effect, and by taking advantage of it many 

 electrolytic substances can be introduced through 

 the skin under the impulse of the electric current. 

 The coagulation of plasma forms no obstacle to the 

 entrance of such ions, and their action will be in 

 proportion to the permeability of the proteins to 

 the ions. 



In the direct ionic application the electrodes are 

 covered by fifteen to twenty layers of- absorbent lint 

 or other tissue and well soaked in the solution to be 

 ionised. Fresh tissue must be used at each sitting. 

 The solution must be made with pure distilled water, 

 otherwise the introduction of undesired ions may 

 result. Iodine ions can be introduced into the 

 thorax by this method. The solution of sodium or 

 potassium iodide is applied on absorbent tissue to 

 the cathode and this to the affected part, and a 

 current of 60 to 100 milliamperes is sent through it. 

 The ions have a great speed, for they are driven not 

 only by the electro-motive force, but by the high 

 osmotic pressure ; and in ten to fifteen minutes 

 iodine appears in the saliva and can be detected by 

 starch. The solution must be applied by the 

 cathode, for if it be applied at the anode no iodine 

 will be found in the saliva, f This mode of treatment 

 may be used in thoracic diseases, in ankylosis, 

 scoliosis, old neuralgias, and other ailments. Ions * 



* Brit. Med. Jour., 1907, ii., 631. 

 f Loc. cit. 



