Blister Canker 
43 
ered with rubberoid roofing as in the case of the tubs already- 
mentioned, to prevent evaporation and a consequent concen- 
tration of the nutrient solution. 
A record was kept of the amount of solution used by each 
tree and the amount of gro\vth made. Table 11 shows the 
relative amount of fungous gro\\i:h for trees in each solution 
compared with the amount in trees which were inoculated at 
the same time and set in soil. 
The least infection was found in trees set in soil. These 
trees made a much more satisfactory growth than any of the 
trees supplied with nutrient solutions. Of the trees supplied 
with nutrient solutions those receiving a 0.2 per cent complete 
solution made the most satisfactory growth and showed the 
least infection. Trees grown in solutions of higher concentra- 
tion (0.4 per cent and 0.6 per cent) were badly infected and 
made little growth. 
The osmotic pressure of the 0.6 per cent solution was so 
great that it was impossible for the trees to obtain sufficient 
water to maintain gro\vth. All but one of the trees lost their 
leaves and were practically dead above and below inocula- 
tions. The same conditions obtained, but to a lesser degree, 
for the trees in 0.4 per cent solution. The trees in 0.1 per cent 
solution made little growth but, except for a stunted appear- 
ance, remained apparently healthy. They were more heavily 
infected than the trees in soil or those receiving the 0.2 per 
cent solution. 
There was so much variation in the amount of infection 
and such a difference in the amount of growth made by the 
individual trees that no reliable conclusions can be drawn. All 
of the trees made some but in no case a satisfactory growth. 
Even the trees with no nitrogen made considerable leaf growth 
altho there was practically no root growth. The only definite 
statement which can be made is that the greatest infection 
was always found in trees which had made the least growth. 
The supply hose in one of the jars became clogged. This 
was not noticed until several days later when the feeding jars 
were being replenished. It was noticed that none of the solu- 
tion in this jar had been used, and that the leaves of the tree 
were wilting. The obstruction was removed but the tree did 
not recover. The hose in three other jars were then stopped 
for five days with like results. All of these trees (indicated 
in table 11 by *) were as badly infected as those grown in the 
solutions of high concentration. 
