Studii-s on Crown Gai.i. of Plants 439 



host." He realized that superficially crown t;all *' i^rowths are like 

 those due to various fungi, to gall insects, to Phisnioiiiophora bras- 

 sicae, or to tiie olive-tubercle organism, hut structurally," he 

 argued, " they are different. Their manner of growth and their 

 histology strongly suggest certain malignant animal tumors." "" 

 He was discussing only resemblances, facts of an analogy ad- 

 mittedly incomplete as yet, between crown gall of plants and 

 malignant animal tumors, and his discovery in 1911 that a distinct 

 strand of tumor tissue could be traced from primary to secondary 

 tumors lent credence to his point of view. But he qualified the 

 proposal: 



There is perhaps no metastasis, in the strict sense of the term, but so 

 far as regards the mechanism of tumor development it is a matter of minor 

 importance wheUier the migrating tumor cells separate themselves entirely 

 from the parent mass or remain connected with it by means of a tumor 

 strand. The plant body favors the latter method of development, whereas 

 the rapidly circulating blood stream in animals favors the former, i. e., the 

 dislodgment and distribution of cells. The matter of chief importance is 

 the method of action of the parasite on the cells of the host.*'^ 



It was a worthy faith, but Smith advanced no more than a hope, 

 that " some light " on the origin of malignant human tumors 

 might be disclosed from his researches. That the light began to 

 have faint glimmerings around the world was in part due to Dr. 

 Gaylord. fn October 1910 he attended the International Cancer 

 Congress at Paris and heard Dr. C. O. Jensen of the Serum 

 Laboratory of the Danish Veterinary and Agricultural School at 

 Copenhagen address the conference. When Dr. Jensen expressed 

 a belief that his experimental tumors on beets were probably 

 non-parasitic in origin, Dr. Gaylord informed him of Smith's 

 discovery and isolation of the parasite Bacteritwi tinnejaciens. 

 Jensen procured a copy of Smith, Brown, and Townsend's bulletin 

 213, "Crov/n-Gall of Plants: Its Cause and Remedy," and, after 

 studying its contents and himself performing further experiments, 

 began to share the view, quoting him, " that ' crown-gall ' is a 

 new formation which (irrespective of the cause of its formation) 

 can be placed side by side with the real malignant tumor-forma- 

 tion in the higher animals. . . . Through all these properties thi< 



"E. F. Smith, Crown gall of plants, Phytopathology 1(1): 10, Feb. 1911. 

 •■^ Crown-gall and sarcoma, Cicular 85, op. cit., 1-4, at p. 1. 



