Ri-si;ar( n on Plant Tumors 493 



nature of crown j^all. He experimentally sexiireJ in plants a series 

 of results of " embryonal teratomata " which he believed tended 

 to correlate " the most diverse forms of neoplasm " and removed 

 one of the strongest objections to regarding crown gall as a cancer 

 in plants." 



The facts of his discovery were described '''' in part as follows: 



[U]p to the winter of 1915-1916 I do not recall that I ever saw a bud 

 or shoot on a gall known definitely to be a crown gall. Early in our study 

 of this disease, however, we demonstrated by cultures and by inoculations 

 on apple, quince, and sugar-beet that a root-disease of the apple charac- 

 terized by small flat tumors out of which grow tufts of flesliy roots and 

 which was supposed 'to be a disease of non-parasitic origin, was actually 

 due to bacteria scarcely distinguishable morphologically and culturally from 

 those causing the ordinary crown gall. I was then inclined to assume com- 

 plete identity of the organisms and to ascribe the difference in the pheno- 

 mena, i. e., plain galls, or root-bearing galls, to fundamental diflPerences in 

 the tissues which happened to become infected, since the parasitic bacteria 

 were not found in the new roots but only in the flat and often scanty tumor 

 from which they originated. . . . Clusters of roots were also obtained on 

 the stem of a collard plant which was inoculated with the crown-gall 

 organism plated from a tumor on poplar, which tumor did not bear roots. 

 To this extent only had I seen formed organs develop out of experimentally 

 produced tumor tissue. Now I have seen much more, to wit, imperfect and 

 fugitive leaf -buds and flower buds also developing from crown galls pro- 

 duced by pure-culture inoculations, using the hop strain of Bacterium 

 tumefacieus. These were first observed January 8, 1916, in shoots of red- 

 flowered Pelargonium inoculated in the growing point, five at least out of 

 six plants showing the phenomenon. . . . More recently by bacterial 

 inoculation restricted to the region of dormant buds in leaf axils, I have 

 obtained the same phenomena on tomato and tobacco plants, on orange 

 trees, on castor oil plants, and again on Pelargonium. Still later, on a 

 tobacco plant by direct inoculation, i. e., without the intervention of a 

 tumor-strand I caused a shoot to develop out of place, i. e., beloti/ a leaf 

 rather than from the axil above it — an unheard of phenomenon ! 



The discoveries of January 8 had been made soon after Dr. 

 Smith had addressed,"*^ at the invitation of the Surgeon General, 

 a meeting of the second Pan American Scientific Congress. On 

 January 6 he had presented a lantern-slide demonstration of 

 " Plant Tumors " before a joint session of subsection E of the 



'^* E. F. Smith, Studies on the crown gall of plants, its relation to human cancer, 

 Jour. Cancer Research 1(2): 231-309, at 243, and n. 3, Apr. 1916. 



" Ue?n. 241-242, and n. 2. 



^^ Second Pan Amer. Set. Cong. The Final Act, 279, Washington, Gov't Print. 

 Office, 1916. Surgeon General Wm. C. Gorgas was chairman. 



