A. M. Taylor 255 



covered with a film of water in the ordinary course of watering and the 

 success of the experiment depended upon keeping all of the buds 

 dry. It must be noted here that it was possible to almost eliminate 

 atmospheric condensation in the greenhouse in which the plants were 

 kept. Inoculation in this experiment was effected by placing diseased 

 buds in a heap round the stems of the seedlings. 



After a six weeks' period microscopic examination of the seedlings 

 thus treated shewed that no infection by worm of the aerial buds of the 

 seedlings had taken place. The basal buds, however, which are pro- 

 duced below the surface of the soil and which are often as well developed 

 as the terminal buds of the shoots, were in all instances badly infected 

 with worm and in an advanced stage of decay. The stems were dissected 

 and examined microscopically as were the roots. They shewed however 

 no sign of the presence of worm, neither was there any discoloration of 

 the tissue such as would occur had the worms lived there parasitically. 



It will be convenient as each section of the experiment is dealt with 

 to sum up the points that appear to be established with regard to 

 migration, and to follow up suggested lines as they occur. 



The foregoing experiments appear to establish the following points : 



(i) That the worms do not invade the buds if the stems of the 

 plants are kept under dry conditions. 



(ii) That they can, on the other hand, penetrate the soil and infect 

 the basal buds beneath the surface under the condition of moisture 

 supplied by the ordinary course of watering. 



(iii) That they do not enter the roots of the plants and gain access 

 to the buds by the internal tissues of the stems. 



Ectoparasitic habits are thus suggested. 



Section II. 



In this section an endeavour was made to discover whether migration 

 could be carried out if the vegetative parts were subjected to an excess 

 of moisture. 



For this purpose it was proposed to keep the experimental plants 

 under strongly contrasting conditions to those of the foregoing section. 

 The seedlings were therefore embedded to the rim of the pots in sand 

 which was kept moist throughout the experiment and over the plants 

 tbus treated bell- jars, having their rims tightly pressed into the sand, 

 were placed. In addition to this treatment the plants were sprayed 

 night and morning with a fine spray producer. Inoculation was effected 



