32 CROWN-GALL OF PLANTS. 



was inoculated. The inoculations were made into soft stem tissues 

 and leaf tissues at the top of the shoot. The method was to take out 

 a little of the agar slime on a platinum loop, rub it gently over the 

 surface, and prick through it with a delicate steel needle, making a 

 dozen or more light punctures. Five daisy plants were inoculated 

 with the same culture for controls. 



Result. — May 21, 1908: The shoots are now about 15 inches to 2\ 

 feet high. Glossy swellings in the pricked areas began to appear after 

 a few weeks and were especiall}^ pronounced on the variety known as 

 Single White, so that at first it seemed as though the other 2 varie- 

 ties would prove immune. But they soon showed distinct, small, 

 ruptured (corky) tumors which grew slowly. The results by plants 

 on this date are as follows: 



Plant A, Madame Peyre: The top of the shoot which was inoculated has grown 5 

 inches beyond the punctured part. That part now bears 12 tumors, which are small 

 but decided, there being no doubt whatever as to their nature. Their height is about 



2 millimeters and their breadth about the same. 



Plant B, Madame Peyre: This slioot has grown about 4 inches beyond the punc- 

 tured part. The tumors have fused so that the exact number can not be stated, but 

 there is a knobby mass where the plant was punctured. The size of the fused portion 

 may be about 6 by 4 millimeters, and the height of it perhaps 3 millimeters, and around 

 this are a few independent small tumors. 



Plant C, Professor Parlatore: This plant has grown about 8 inches beyond the punc- 

 tured part; there are 9 distinct small tumors and a couple of fused ones. Their height 

 is about 3 millimeters, and their diameter 2 to 3 millimeters. Surface somewhat brown 

 and roughened, which is true of all of the larger tumors. 



Plant D, Single White: This shoot has grown about 3 inches beyond the punctured 

 area. The punctured part bears about a dozen tumors, some fused; the largest is about 



3 millimeters high by 3 to 4 millimeters broad, with a roughened surface. The small- 

 est one still has the smooth, shiny, unbroken skin characteristic of all of them on the 

 start, and characteristic also of the smallest tumors observed on the oleanders received 

 from Fresno, Cal., this spring. « 



Plant E, Professor Parlatore: This plant has shown less reaction than any of those 

 hitherto examined, probably because the inoculated shoot has made less growth. The 

 growth beyond the punctured area is only about 1^ inches, and there are only three 

 small tumors, each about 1 millimeter high and the same in diameter. Fifteen other 

 needle punctures appear to have given no reaction. 



Plant F, Single White: This is a tall plant of a single stalk and is now in blossom. 

 Since the punctures were made it has grown about 10 inches (beyond the pricks) and 

 developed the blossom stalk. In all of those hitherto described the tumors have been 

 on the stem, but 4 of the tumors on this plant are on the base of a petiole and 5 are on 

 the stem. Three additional pricks have not developed anything. The larger of 

 these tumors are estimated to be 3 millimeters broad and about 2 millimeters high, 

 surface roughened. Distinct overgrowth. 



Plant G, Madame Peyre: Shoot has grown about 4 inches since it was inoculated, 

 and it bears 10 separate tumors (one fused out of about 4) and 4 punctures that have 

 not given any distinct growth. One of the little tumors is on the base of a petiole. 



o The organism causing the Kresno disease is probably not identical with the one here described.— E. F. S. 

 213 



