BY J .f. FLETCHER AND C. T. MUSSON. 197 



been produced with Barter ium tumefadens The plants 



chiefly experimented on have been Pelargonium, Nicotiana, T.y- 

 copersicum, Citrus, and Ricinus. All of these and some others 

 (Mangifera, Allamanda, etc.) have yielded teratoid tumors 

 from inoculations in leaf-axils/' 



In a later paper, Dr. Erwin Smith refers again to the acci- 

 dental circumstance which suggested to him the desirability of 

 inoculating plants in leaf-axils and growing-points, in addition 

 to internodes, as he had been doing for years. " We had found 

 indeed, as early as 1908-9, and had produced by bacterial inocu- 

 lation, plant-tumors bearing roots, but the full meaning of this 

 discovery, as related to cancer, did not occur to me until early 

 in 1916. when I found crown-gall tumors bearing leafy shoots on 

 some of our inoculated hothouse geraniums. Beginning with 

 this discovery, I made numerous inoculations in the leaf-axils of 

 various plants, which resulted in the production of leafy tumors, 

 and subsequently I produced them on leaves and on cut inter- 

 Tiodes where no buds occur normally. Tumors bearing roots have 

 also been produced by us on the top of plants, and in one cut 

 internode of Tobacco I succeeded in producing a tumor which 

 bore flower-buds. These perishable root-bearing and shoot-bear- 

 ing tumors I regard as plant-embryomas, and have so described 

 them [Journ. Cancer Research, April, 1916, p. 241]." 



We have not had access to the paper last mentioned. Rut in 

 the Johns Hopkins Bulletin for September, 1917, Dr. Erwin 

 Smith has given further particulars, and numerous illustrations 

 of the embryomas resulting from his inoculations, together with 

 two (fig.63) of "Pelargonium teratoid tumors originating natu- 

 rally ... on gardener's cuttings bedded in earth for propagation. 

 The specimens came from a gardener's house near Jjaltimore." 



We give the following brief extract from this paper — "In 

 April 1916, I announced the discovery of a new type of 

 crown-gall, i.e., one containing numerous leafy shoots, and showed 

 that I could produce it at will by making my bacterial inocula- 

 tions in leaf-axils where there is a dormant bud I have 



since discovered that leafy crown-galls occur in nature on various 

 plants, e.g , on the rose, and on the carnation." 



