98 CROWN-GALL OF PLANTS. 



from the poured- plate colonies. The stems of the tomatoes were not 

 inoculated. 



Result. — February 2, 1909: No appearance of galls or hairy roots. 



HARD GALL OF APPLE ON PELARGONIUM. 



Inoculations of November 9, 1908 (Smith). 



Two growing shoots of Pelargonium were inoculated from poured- 

 plate colonies made November 4 from the hard gail of apple received 

 from Iowa. These inoculations were from the same plate as the 

 daisies inoculated on this date and were made in the same manner 

 (p. 96). 



Result. — November 16, 1908: As yet no indications of tumors on 

 any of the plants. 



April, 1909: No tumors appeared. 



Inoculations op June 24, 1910 (Smith). 



Ten growing shoots of Pelargonium zonale (pink and red flowered 

 varieties) were inoculated in the soft terminal portion by needle 

 pricks from an agar streak culture 2 days old. This was descended 

 from a colony isolated in 1908. Four similar shoots were pricked 

 with a sterile needle as checks. 



Result. — August 10, 1910: Negative. 



October 21, 1910: Negative. 



HARD GALL OF APPLE ON APPLE. 



Inoculations op January 23, 1908 (Smith). 



Inoculated 10 growing Wealthy apple trees, part of them on the 

 stock, with a bacterium plated from a hard knot on an apple tree 

 furnished by Doctor Iledgcock (first D. C). The roots were washed 

 thoroughly and 50 or 60 pricks on each tree were made in some 

 pecuhar form, so as to recognize the place of inoculation. The gray- 

 white slime from 44-hour-old slant agar cultures grown at 30° C. 

 (5 subcultures, all descended from one small, white colony) was 

 used for these inoculations. These cultures came from three 10-day- 

 old slants and those from stock cultures made from the colony. 

 After inoculation the trees were planted in 10-incli pots in the green- 

 house. 



Result. — No infections. Trees continued to grow, but very slowly. 

 The colony used was, perhaps, a wrong one. Many small round white 

 colonies appeared on the set of plates from which this colony was 

 selected, 



213 



