548 Crown Gall-Animal Cancer Analogy 



Society of America in a symposium on mosaic diseases of plants. 

 Four of the fourteen papers — one by Kunkel — reported finding 

 " definite bodies of organisms in the tissues of plants affected 

 with mosaic." H. H. McKinney, Sophie Eckerson, and R. W. 

 Webb described finding intracellular bodies in mosaic of Hip- 

 peastrum johnsonii and rosette disease of wheat. These "many 

 interesting papers " made Smith ' live a month in this day. , . . 

 Fourteen papers on Mosaic diseases," he exclaimed, " including a 

 magnificent one by Ray Nelson on Trypanosomes and related 

 forms in four plants — bean mosaic, clover mosaic, tomato mosaic 

 and potato leaf roll." Illustrated by beautiful photomicrographs, 

 Nelson's paper received an ovation. Two papers by Dr. A. J. 

 Riker on crown gall were of much more than usual interest, but 

 these will be considered at a later point in our narrative. 



The symposium on mosaic diseases of plants was regarded as 

 " an important milestone in the progress of plant pathology." ^^ 

 During the next year, in Phytopathology, would appear an abstract 

 of Nelson's paper on " The occurrence of protozoa in plants 

 affected with mosaic and related diseases." '° Following the pub- 

 lication of his bulletin '^ from the Michigan Agricultural Experi- 

 ment Station, other studies were made and published.'" Charles 

 Atwood Kofoid, eminent protozoologist, and some co-workers at 

 the University of California, however, were unable to agree that 

 the organisms believed to be " a flagellate of new generic rank" 

 were either trypanosomes or of " a protozoan nature." Nor were 

 such " as might be expected in an organism with trypanosome 

 affinities, or, indeed, of any known protozoan type." "^ 



Smith was aware that, emerging more or less from the recent 

 study of mosaic diseases of plants, a " great revival of interest in 

 ' virus ' diseases of plants," ^* was taking place. In fact, in his 

 own laboratory during the first half of the year 1922, he and his 

 co-workers had been studying the tomato streak virus, so-called. 

 His intention was presented in an address " of that year: 



^^Phytopathology 13:33-60, 188-198, 1923. 

 ""^ Phytopathology 13(1) : 41, Jan. 1923. 

 '^ Mich. Agr. Exp. Sta. Tech. Bull. 58, 1922, 30 pp. 

 '-Phytopathology 13(7): 324-325, 326-329, July 1923. 



'"'Idem, 330-331. See also, Harold Kirby, Charles Atwood Kofoid 1865-1947, 

 Science 106(2759): 462-463, Nov. 14, 1947. 

 ''*' Fifty years of pathology, op. cit., 35. 

 '® Twentieth century advances in cancer research, op. cit., 317. 



