40 CROWN-GALL OF PLANTS. 



the position of the needle pricks. They vary in number from 1 to 3 

 on each plant. 



Of the 18 plants showing larger tumors 13 were inoculated from 

 the older cultures and 5 from the younger. All the tumors are on 

 the main root, with the exception of one, which is on a small side 

 root, and appears to be a secondary infection. The others seem to 

 be primary infections, but not every group of needle punctures re- 

 sulted in a gall. The tumors on these plants vary in number from 1 

 to 4. On plant 137 (which received 30 pricks in 6 groups) only one 

 tumor resulted. 



General remarks. — Of these plants 73 per cent show tumors. The 

 plants were neglected on the start, receiving too little water, and 

 for this reason made a very slow growth for several weeks after 

 they were planted in pots in the hothouse. They have also fre- 

 quently since that date received too little water. 



Photographs were made of the best of this material (PI. XI, fig. 2). 



Respecting the group which shows no tumors, it ma}^ be stated 

 that there is some evidence to show that some of those marked nega- 

 tive may have developed little tumors wliich afterwards perished. 

 The bulk of the tumors are still sound, but a dozen or more have 

 decayed more or less, and a few pretty completely; and if the same 

 thing had happened to much smaller tumors on the first group, then 

 there would be now no e^ndence of infection, although there might 

 have been evidence two months ago. 



Considering the slow growth of the trees the results are fairly satis- 

 factory, especially since all the 21 check trees (420 punctures) have 

 remained entirely free from tumors, although the trees made more 

 growth than the inoculated ones which developed the galls. The 

 check trees have been in the same hothouse, but removed about 30 

 feet from the inoculated ones. The soil was the same. 



DAISY ON ALMOND. 



Inoculations of March 7, 1908 (Smith). 



Bight seedling hard-shell almonds v\'ere inoculated at the crown 

 with 48-hour-old agar slants of the Aai&j organism. 



Result. — March 18, 1908: One of the inoculated almonds was dug, 

 and a small, well-developed tumor found at the entrance of the 

 needle. 



March 28, 1908: Two more plants dug. Nothing definite found. 



March 31, 1908: The remainder of the plants were dug; 3 were 

 found with small tumors; 2 without. The plants have stood from 

 the time they were germinated in clean sand, and only when they 

 were inoculated was an inch of gardeners' earth put on top of the 



213 



