144 



Scientific Proceedings (53). 



of the animals which received digitonin alone and two of those 

 which received digitonin and lecithin died within a few hours 

 after the treatment. Post-mortems showed that the heart had in 

 each case stopped in extreme systole, the auricles being engorged. 

 In subsequent treatments the dose of digitonin was reduced to 

 I c.c. of a 0.5 per cent, suspension, and in the case of the animals 

 which received lecithin, the concentration of the lecithin emulsion 

 was increased to 2 per cent. In the course of these treatments 

 two more of the animals which received digitonin and lecithin 

 died, in each case post-mortem examination showed that the 

 heart had stopped in extreme systole. 



Treatments were given on the 20th, 22d, 25th, 27th, and 29th 

 days after the inoculation. 



It was found that twenty-four hours after the first treatment 

 the tumors were soft and pulpy and also presented a discolored 

 appearance. The tumors rapidly hardened again, however, and 

 those which were treated with digitonin alone grew much more 

 rapidly than the controls or the tumors which were treated with 

 digitonin and lecithin together. This is shown by the following 

 figures, the diameter of the tumors at the beginning of treatment 

 being taken as 100 in each case. 



Diameter of the tumors. 

 20 days after inoculation. 25 days after inoculation. 



Controls 100 114 



Digitonin 100 146 



Digitonin + lecithin 100 113 



It is evident that lecithin antagonizes the action of digitonin 

 in accelerating the growth of carcinoma. This we have confirmed 

 by further experiments which will be reported in a later com- 

 munication. 



Thirty per cent, of the controls, thirty per cent, of the animals 

 which had received digitonin alone, and twenty-five per cent, of 

 the animals which received digitonin together with lecithin had 

 undergone "spontaneous cure" 32 days after inoculation. 



In order to ascertain whether or not the above effects were 

 due to digitonin itself or to some impurity contained in Merck's 

 preparation, we prepared pure digitonin by dissolving Merck's 

 digitonin in alcohol, pouring this solution into a large volume of 



