64 CEOWN-GALL OF PLANTS. 



shaped, sharply pointed, and most of them had broken through to 

 the surface, while others were doing so. The only crystals in the 

 plate were inside some of the yellow colonies. There were about 30 

 of these yellow colonies. The surface of the knot was probably not 

 bathed in 1 : 1,000 mercuric cliloride water long enough, i. e., only 10 

 seconds. Subcultures were made from 10 colonies on 2 of the 

 thinnest sown plates, and 10 other similar white colonies on the 

 plates were used to make the successful inoculations of February 3. 



Inoculations of February 3, 1908 (Smith). 



Ten daisy plants, Nos. 40 to 49, inclusive, were inoculated with the 

 peach organism (originally plated from crown-gall of the peach, 

 inoculated December 4 into daisy with production of tumors; then 

 on January 27, plated from one of these tumors and now reinocu- 

 lated into this group of daisies). The plants were each inoculated 

 from a separate poured-plate colony. 



Result. — June 1, 1908: Each of the 10 daisy plants finally devel- 

 oped a tumor (from one-fourth inch to over an inch in diameter) in 

 the inoculated spot; but they were very slow to appear. They 

 showed no tumors in any other place except No. 48, which developed 

 a small tumor at the surface of the ground about a foot below the 

 inoculated part. Photographs made (PI. XIII, fig. 2). 



Inoculations of March 11, 1908 (Smith). 



Two daisy plants were inoculated with peach organism from colo- 

 nies on poured plates of March 4. Two plants were held as checks. 



Result. — June 1, 1908: No tumors; none on checks. These daisy 

 plants were inoculated as checks on Wealthy apple, inoculated with 

 the peach organism from the same poured plates, and their failure to 

 produce tumors was due probably to small amount of inoculating 

 material left after inoculating the apples (since the latter contracted 

 the disease), or to the fact that they were inoculated directly from 

 the plate, as would seem to be the case, from similar looking but really 

 different colonies, or finally to the possibility of the daisy cuttings 

 having been made from somewhat resistant (previously inoculated) 

 stocks (p. 177). 



PEACH ON OLIVE. 



Inoculations of March 11, 1908 (Smith). 



The tops of 2 tender shoots were inoculated with the peach organ- 

 ism from poured-plate colonies of March 4. 



Result. — June 1, 1908: One of the inoculated shoots had grown 15 

 inches since the date of inoculation and the other one about 10 

 inches. No tumors. 



213 



