534 Crown Gall-Animal Cancer Analogy 



Dr. Gaylord and Smith exchanged some letters in September, 1920, 

 concerning a similar study published recently in the Journal of 

 Cancer Research by Levine and Dr. Isaac Levin. Dr. Smith's 

 laboratory was still, first and foremost, one of plant pathology. 

 He tried in every way practical to perfect his technique in studying 

 crown gall. He had been " trying for two or three years to get 

 hold of Dr. Bovie's apparatus for registering, electrically, the exact 

 acidity of culture media " '' to improve his study of the hydrogen- 

 ion concentration in tumors of plants and thus his study of the 

 crown gall-cancer analogies. 



By a letter of January 8, 1924, Smith explained to Dr. John M. 

 T. Finney of the Johns Hopkins Hospital his hopes and intention: 

 " I do not consider it at all likely that I shall ever be able to 

 settle the cancer question. I only may have thrown some side 

 lights on it which might help somebody working directly in that 

 field to solve it. That is the most I have ever hoped to do, and 

 sometimes I feel as if I had not done even that." 



Dr. Charles Oberling, in his recent book, The Riddle of 

 Cancer, ^^ has said: 



Nearly every organism advanced as the cause of cancer has turned out 

 to be a familiar and harmless inhabitant of the skin or mucous membranes, 

 and not a single one, whether isolated from man or from the lower animals, 

 has ever elicited a genuine neoplasm. The only exceptions are certain plant 

 tumors, caused by a microorganism {Bacillus tumefaciens) isolated and 

 described by Erwin F. Smith. 



Discussing the three more important hypotheses of the origin 

 of cancer — the irritation, the embryonal, and the parasitic, or 

 microbic — Dr. Oberling drew from numerous instances of results 

 of modern research in virus diseases of plants and animals. 



Smith, like many other students, found truth in all three hypo- 

 theses. While to the parasitic theory he subscribed more zealously, 

 he did so largely on the basis of his learning in bacteriology and 

 to some extent fungology. A student of parasitic diseases might 

 be expected to indulge some bias, especially where the behavior of 

 a pathogenic organism indicated analogous action. But prejudice 

 was an unwritten word in his scientific language. He sincerely 

 believed that the behavior of plant cancer was similar to animal 



*' Letter, Smith to L. R. Jones, Mar. 11, 1920. 

 ^'New Haven, Yale Univ. Press, 1944, p. 35. 



