88 CROWN-GALL OF PLANTS. 



December 22, 1908: The hop-galls had increased so that they were 

 now one-half to three-fourths inch in diamater. No galls formed on 

 the adventitious tomato roots inoculated with the hop organism. 

 The checks remained healthy. 



February 15, 1909: Photographs were made (PI. II, fig. 3). 



HOP ON OLIVE. 



Inoculations of May 9, 1910 (Smith and Brown). 



Ten rapidly growing olive shoots were inoculated near the tip by 

 needle pricks from a young agar culture. For want of other material 

 these inoculations were made on plants standing close together in a 

 bed. Many of these bore olive tubercles as the result of recent inocu- 

 lations, and other inoculations with the same organism (Bacterium 

 savastanoi) were in progress at that time. 



Result. — July 18, 1910: All negative except No. 4, which bears 25 

 needle pricks, from 3 of which small galls have developed. Possibly 

 these are olive galls, as branches of the same plant were by accident 

 inoculated two days later with the olive-tubercle organism and the 

 gardener sprayed the plants every day.'' Otherwise it is difficult to 

 account for the 9 failures, as the shoots have grown very rapidly since 

 inoculation, i. e., 16 inches to 2 feet, and were all inoculated with 

 equal care and from the same culture. 



December 7, 1910: Plates were poured in gelatin from one of these 

 galls and only the olive-tubercle organism was isolated, thus con- 

 firming the previous supposition. 



HOP ON COTTON. 



Inoculations op July 20, 1910 (Brown). 



Inoculated 6 young growing cotton plants (Willet's Red Leaf) at 

 the crown with 5-day-old cultures of the hop-gall organism. Two 

 checks were held. 



Result. — October 21, 1910: All negative; growing conditions good. 



HOP ON GRAPE. 



Inoculations of April 16, 1909 (Brown). 



Eight young shoots of European grape on 3 plants, variety not 

 known, were inoculated with agar streak cultures 2 days old. The 

 crowns of the 3 plants were inoculated also. Two plants were held as 

 checks, the stems and crowns being punctured with a sterile needle. 



Result. — May 6, 1909: The stems of the inoculated vines had small 

 knobbed prominences hke the regular grape gall. No galls showed 

 on the crown. 



a The strain of the olivr-tubrrclo organism used proved very infections, every one of the 208 inocula- 

 tions yielding a gall with i.iany subsequent metastases, although all of the lOa.inoculated plants had pre- 

 viously borne galls, and two former strains (one from California, one from Italy) had ceased to be infec- 

 tious lo them. The recent strain was isolated from an olivo knot sent by Miss Florence lledgesfrora 

 I'ortofino, Italy, in April, 1910.— K. F. S. 



