But it does differ from almost all other 

 therapeutical agents in the fact that, it 

 has such a vast field of applicability in 

 which the indications for its use are 

 supported solely by clinical evidence 

 and in which its action defies all at- 

 tempts at an explanation of results at- 

 tained, on a physiological basis. 



Although the practitioner may not 

 be able to satisfy his ethical desire to 

 explain the action of preparations of 

 iodine in the latter class of pathological 

 conditions, he soon makes the discovery 

 that these actions and results are, to a 

 very considerable degree, dependent 

 upon more or less well-marked clinical 

 and physical phenomena. In order to 

 be able to give to his use of iodine, in 

 its various forms, even a semblance of 

 ethical practice, and, also, in order to 

 be able to roughly classify and select 

 the conditions in which he may use 

 iodine with some expectation of uni- 

 8 



