Malignancy of Crown Gall. 



21 



injuries inflicted upon the central nervous system by the tetany 

 toxin. These nervous lesions develop even in the presence of cal- 

 cium or magnesium and even without any convulsions at all, and 

 finally lead to the death of the animals. 



The most dangerous and important action of the tetany toxin 

 is its highly injurious effect upon the central nervous system as 

 expressed by the lesions of the muscular system (permanent spas- 

 modic contractions and paralysis). The most important function 

 of the parathyroids is to prevent the tetany toxin from coming 

 in contact with the central nervous system, and this function 

 cannot be substituted by any substance such as calcium or mag- 

 nesium, since these substances do not antagonize the tetany toxin. 



15 (i39o) 



Malignancy of the crown gall and its analogy to animal cancer. 

 By Isaac Levin and Michael Levine. 



[From the Department of Cancer Research of the Montefiore Hospital 

 and Home, New York.} 



In a study reported recently on the influence of X-Rays on the 

 development of the crown gall the writers have come to the con- 

 clusion that this growth presents an ideal material for the cellular 

 study of the cancer problem. Dr. Erwin F. Smith, of Washing- 

 ton, considers this parasitic disease of plants to be identical wiih 

 human cancer to such an extent that since crown gall is caused 

 by a microorganism he maintains that all human cancers must be 

 due to the same parasite. It seemed desirable to repeat Smith's 

 experiments from the standpoint of human pathology and this 

 was the object of the present investigation. 



A large number and a great variety of plants were inoculated 

 with a pure culture of Bacterium tumefaciens and a gross and 

 microscopical study of the resulting crown galls was made. The 

 analysis of the material shows that a certain number of these 

 plant-tumors behave morphologically as well as biologically as 

 benign growths. They grow very slowly, do not interfere with 

 the development of the inoculated plant, compress but do not in- 

 jure the neighboring normal tissues. Other crown galls appear to 



