SYMPOSIUM ON RADIOACTrV'ITY. 79 



their destruction. The whole process is one of exaggerated stim- 

 ulation of the activit>- of the cells of the tissues; a stimulation 

 which varies in degrees with the degree of speciaUzation or func- 

 tional activity of the different t}-pe of cells. In its slightest 

 degrees it is the ordinar}- protective process that occurs under 

 exposure to sunlight, but under the unusual and extreme irritation 

 of this artificial form of radiant energ)' the reaction becomes 

 destructive. 



Since the effects of radium have had therapeutic appHcation. 

 it may be interesting to pause to consider briefly this aspect of 

 the subject. 



As I have suggested, the effects of radium are to a degree 

 selective, in that they excite the intensest reaction in the cells of 

 great functional activitiy, whether this be in the exercise of a 

 special function or of the simpler function of growth. Thus 

 there is produced by radium : 



(1) An exaggerated effect upon the highly specialized struc- 

 tures of the epidermis, viz.. the hair follicles, and the sebaceous 

 and sweat glands, and likewise upon the basal or germinal layer. 



(2) An endarteritis or proHferation of the Hning membrane of 

 the blood vessels, which may lead to obliteration of many blood 

 vessels. 



(3) Destruction of masses of diseased tissues, which are com- 

 posed of young growing cells or immature cells. 



These effects upon tissues suggest the possible use of radium 

 for various therapeutic purposes, as follows : 



(1) To effect the tissues by stimulating them. This has been 

 used in an empirical way in the treatment of various chronic 

 inflammatory processes in the skin, usually of uncertain origin. 



(2) To destroy or diminish the follicles of the skin, particularly 

 the hair follicles. This principle has had practical appHcation 

 with X-rays, but because of the small quantities available, not 

 with radium, except in the treatment of hairy naevi or birthmarks. 



(3) To obliterate blood vessels in the skin. This has had 

 practical application, with very successful results, in the treat- 

 ment of vascular naevi or birthmarks. 



(4) To destroy pathological tissues. This use is of course 

 possible of wide application, and has been successful in various 

 diseases of the skin and the adjacent underlying structure, espe- 

 cially in carcinomas and sarcomas (cancers). Its limitation in 

 cancer is that it is only effective upon such lesions as can be 



