EXPERIMENTS WITH THE GRAPE ORGANISM. 57 



Inoculations of June 28, 1910 (Smith and Brown). 



Eleven small seedling almonds and 1 grafted almond were 

 inoculated on the crown by needle pricks from a young slant agar 

 culture, not of the same origin as the preceding. 



Result. — July 18, 1910: Galls are forming on the crowns of several 

 of these plants. 



July 29, 1910: Plants dug; 100 per cent infected. Galls occur 

 only where inoculated and are from one-eighth to three-fourths inch 

 in diameter (PL IX, fig. 3). The check plants, 2 pricked and 4 

 unpricked, are free from galls. The grafted plant is S. P. I. 24809, 

 N. E. H. 257. The seedlings were grown from hard-shell California 

 almonds cracked and germinated in sand, after removal of the shell, 

 this spring in one of our houses, and all were free from natural 

 infection. 



GEAPE ON SUGAR BEET. 



Inoculations of August 31, 1909 (Brown). 



Three sugar beets were inoculated with agar cultures 4 days old 

 (same cultures used this date also on grape and daisy). 

 Result. — October 13, 1909: No galls formed on the beets. 



Inoculations of May 7, 1910 (Brown). 



Twelve well-grown sugar beets standing in one row in a bed in the 

 hothouse were inoculated on the upper part of the smooth, white 

 root by means of needle pricks from an agar culture 1 day old. 



Result. — June 23, 1910: Eleven plants contracted the disease at 

 the place of inoculation. One failed; this was a small, slow-growing 

 plant much like those inoculated in 1909. Two other plants in the 

 row, being very small at the time of inoculation, were omitted, and 

 these are now free from galls. The inoculated plants are also free 

 except in the vicinity of the spot where they were inoculated. Other 

 rows of beets in the same bed remained free except as inoculated. 

 The largest tumors are 2 inches across. They resemble the grape 

 gall in having numerous smaller nodules on the swollen surface. 

 (PI. XXIV, B.) 



Remarks. — That these galls were produced by the visible bacteria 

 inserted and not by some invisible hypothetical x transferred along 

 with the bacteria from the original gall and unable to grow in our 

 media but capable of inducing galls when inadvertently put back 

 into the plant along with the bacteria, is indicated by the fact that the 

 following eliminating transfers were made: 



(1) Organism plated from grape gall, August, 1909. 



(2) Subcultures to slant agar from single typical colonies. 



(3) Transfers once a month to agar and beef bouillon for about 7 months to keep 

 the bacteria alive. 



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