Research on Plant Tumors 501 



trying for U/i years to start cpitlulial (inaiiiinary) growths in 

 mice with something besides tumor cells. Results not yet much, 

 but not completely negative." 



Leo Loeb, of the department of comparative pathology of 

 Washington University Medical School, St. Louis, seeing Smith's 

 " interesting papers " in Sciefice and the journal of Cancer 

 Research, sent a collection of their more recent publications. As 

 has been pointed out, Loeb's transplantation to laboratory animals 

 of a rat thyroid sarcoma had preceded the experimental work of 

 even Jensen in Denmark.''" In his address, " Further Evidence that 

 Crown Gall is Caneer," '-' Smith had ventured the opinion that 

 heredity is not a sufficient cancer explanation. " The same thing 

 was said repeatedly," Smith argued, 



of tuberculosis prior to 1884. Now we see that heredity furnished the 

 canvas but could not paint the picture. Miss Maude Slye's work on heredity 

 of cancer in mice is astonishing and praiseworthy, but I do not feci sure 

 that a similar picture could not be obtained by breeding together tubercu- 

 lous animals, indeed I am quite certain that the results of such experiments 

 would be a vastly increased number of tubercular animals, and if we knew 

 no more about the cause of tuberculosis than we do about the cause of 

 cancer, the interpretation of the results would be entirely wrong, ;'. e., they 

 would be ascribed wholly to heredity, whereas we know that two factors 

 are involved: (1) heredity; (2) infection. I do not think Miss Slye has 

 established the fact that cancer follows Mendel's law. 



Loeb had not only taught pathology and experimental pathology 

 at the University of Illinois and the University of Pennsylvania 

 but during 1902 he had been an experimental pathologist with 

 the New York State Pathological Laboratory at Buffalo and until 

 1915 had been for several years director of the department of 

 pathology at the Barnard Skin and Cancer Hospital of St. Louis. 

 Accompanying his collection of publications, he sent a letter to 

 Smith, written on July 3, 1916: 



I was not sure that you had seen our communications dealing with the 

 heredity of cancer, inasmuch as you mention in your resume in Science 

 only Miss Slye's papers. I believe that I was the first one to undertake and 

 to publish extensive studies on the heredity of cancer in isolated strains in 

 animals of the same species, following them through a series of generations, 

 establishing the tumor incidence and tumor age on a large scale. 



Erwin F. Smith, Twentieth century advances in cancer research, op. cit., 291. 

 Op. cit., reprint, 4. 



17 



