30 CROWN-GALL OF PLANTS. 



DAISY ON TOMATO.** 



Inoculations of February 18, 1907 (Smith). 



About a half dozen needle pricks were made on each of 3 soft 

 terminal shoots of as many tomato plants which were about 18 inches 

 high. The organism used was an agar streak culture 7 days old 

 (used also for the daisy inoculations of Feb. 18). 



Result. — Nothing was immediately visible, but after some weeks 

 slow-growing hard tumors developed on each one of these plants in 

 the inoculated part. 



DAISY ON POTATO. 



Inoculations of March 2, 1907 (Smith). 



The stems of 6 potato plants {Solanum tuherosum) were inoculated 

 by needle pricks with agar streak cultures 3 days old. The plants 

 were in pots in the greenhouse. 



Result. — March 27, 1907: Galls developed at all the points of inoc- 

 ulation and are at this date 1 cm. in diameter. One was cut oil" and 

 plates were poured from it. Four days later the characteristic col- 

 onies appeared, and daisy plants were inoculated with subcultures 

 from these colonies. In 15 days small galls had formed on the 

 daisies. 



April 22: Stems cut off and photographed (PI. II, fig. 5a, h). 



Inoculations op March 21, 1907 (Townsend). 



Eighteen plants of Solanum tuherosum were inoculated on the 

 stems. Fourteen of these were inoculated near the tip and four near 

 the base. A number of control punctures were made on other plants 

 at the same time. 



Result. — Galls were formed in 2 to 3 weeks at all of the inoculated 

 points. No galls formed on the control plants. 



DAISY ON TOBACCO. 



Inoculations of February 18, 1907 (Smith). 



About a half dozen needle pricks were made on each of 3 terminal 

 soft shoots on as many tobacco plants, which were about 3 feet high. 

 The material for inoculation was an agar streak culture, 7 days old 

 (used also on daisies of Feb. 18). 



Result. — Nothing was immediately visible, but after some weeks 

 slow-growing hard tumors developed on each one of these plants in 

 the inoculated part and not elsewhere. (For microscopic appearance 

 of a section through one of these tumors see PI. XXIX.) 



oDr. G. P. Clinton, of Connecticut, has reported the finding of crown-gall on bittersweet (Solanum 

 dulcamara). 



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