Influence of Digitonin upon Growth of Carcinoma. 143 



has been observed by Wacker, and that this in its turn is the reason 

 for the well-known increase in the incidence of carcinoma with 

 advancing age. 



93 (789) 



The influence of digitonin upon the growth of carcinoma. 

 By T. Brailsford Robertson and Theodore C. Burnett. 



[From the Rudolph Spreckels Physiological Laboratory of the 

 University of California.] 



It has been shown by Windaus 1 that digitonin combines with 

 cholesterol to form a very insoluble and pharmacologically in- 

 active compound. In view of the marked influence of cholesterol 

 in accelerating the growth of carcinoma we have thought it of 

 importance to ascertain the influence of digitonin upon the growth 

 of Flexner-Jobling carcinoma in rats. 



The digitonin employed was Merck's, stated to have no physio- 

 logical action upon the heart. By heating the preparation to 

 boiling in m/6 NaCl solution a soapy-looking fine suspension is 

 formed which settles out in the course of several hours. We 

 injected the digitonin, suspended either in m/6 NaCl, or in m/6 

 NaCl containing 1 per cent, of lecithin, directly into the tumors. 



One hundred and sixty-six white rats were inoculated with 

 Flexner-Jobling carcinoma in the axillary region. The number of 

 successful inoculations, determined after 20 days, was 64, or 39 

 per cent. 



On the 20th day after inoculation these animals were sorted, 

 without selection, into three batches, of which one (consisting of 

 12 animals) served as controls, another (12 animals) received 

 injections of digitonin, and the third (40 animals) received injec- 

 tions of digitonin together with lecithin. 



We began by administering I c.c. of a 1 per cent, suspension of 

 digitonin, suspended in m/6 NaCl and in m/6 NaCl -f- 1 per cent, 

 lecithin respectively. The animals which received digitonin with- 

 out lecithin evinced symptoms of severe local irritation, and one 



1 A. Windaus, Ber. d. d. Chem. Ges., 42, I (1909), p. 238; Zeit. f. physiol. Chetn., 

 65 (1910), p. 110; M. T. Fraser and J. A. Gardner, Proc. Roy. Soc. London, 82 B 

 (1910), p. 559. 



