CHEMOTHERAPY IN MALIGNANT DISEASE 281 



treatment upon malignant growths also might very well be due to 

 the liberation and action of these very substances. They accordingly 

 studied the effect of various cholin preparations upon tumor growth, 

 and found as a matter of fact that the changes resulting in the tumors 

 were perfectly analogous to those produced by ray treatment. 

 Since cholin could be shown to possess a high power of diffusion 

 the thought then suggested itself, in view of the observations above 

 related concerning the selective action of colloidal metals upon tumor 

 cells, to use the cholin as carrier of these metals. Studies in this 

 direction showed that beneficial effects may indeed be thus achieved 

 in the animal experiment with colloidal selenium, copper, cobalt, 

 iron, zinc, and arsenic, when dissolved in cholin solutions, and that 

 this could be accentuated by combining a metal of high electrical 

 tension with one of low tension, or even with one which in itself 

 is inactive, such as selenium-vanadium, selenium-cobalt, copper- 

 cobalt, etc. There is thus still another avenue open for attack, 

 and one which likewise seems to promise profitable results. 



