24 



Scientific Proceedings (86). 



The optical rotation of the substance was the following: 



122 (1300) 



The influence of X-rays on the development of the crown gall. 



By Isaac Levin and M. Levine. 



[From the Department of Cancer Research of the Montefiore Hospital 



and Home.] 



Crown gall is an infectious disease of plants which may be 

 induced artificially by inoculating with the aid of a needle prick 

 of a drop from an agar culture of Bacterium tumefaciens. Erwin 

 F. Smith, of Washington, who investigated the condition con- 

 tinually for the last 10 years, is of the opinion that the disease is 

 identical with human cancer. Irrespective of the stand one takes 

 in regard to the identity of the two conditions, it must be con- 

 ceded that there is a great deal of analogy between them. Crown 

 gall as well as cancer is a new growth caused by a continuous, 

 limitless proliferation of a group of cells within a tissue which 

 normally do not proliferate at all. As a result of the rapid 

 proliferation the new cells remain young and undifferentiated. 



Clinical and experimental evidence indicates that the main 

 biological and therapeutic action of X-rays consists in inhibition 

 of the proliferating power of young undifferentiated cells. In 

 man and vertebrates the mechanism of the action of X-rays on 

 tumor cells is obscured by the changes in the cellular elements 

 of the blood, lymph and the fixed connective tissue cells of the sur- 

 rounding regions which is always encountered side by side with 

 the changes in the tumor cells themselves. The crown gall, on 

 the other hand, is an ideal subject for the study of the direct 

 biological action of the X-rays on the tumor cells, since there is 

 no other tissue present which may be changed by the rays. 



For the present study ricinus plants and agar subcultures of 

 Bacterium tumefaciens were used. The seeds for the former and 

 the primary culture for the latter were obtained through the 



