13 
cannot, without further proof, be attributed to the effect of the 
inoculation with diseased roots. It may be due to early ans 
and early commencement of decay. The experiment tends 
show that inoculation with diseased material had no effect, since 
of the controls one (B) showed the maximum amount both of 
cracking and of canker, and the other (E) almost the minimum.* 
n addition to the above, efforts were made by means of direct 
checirvatien of\ roots in the Kew plots to follow the course of 
development of the cracks and the subsequent decay. The results 
were not conclusive—a fact which may be partly due to the obser- 
vations being made late in the season, namelv. in September, 
after the return from Worcestershire. Nine prowthaipwtle on 
roots in plot B were carefully examined and measured, the roots 
being left in situ, the soil merely scra tee away for purposes of 
inspection, and replaced at once. The weather was somewhat 
dry for the first ten days after ener ee After two weeks the 
plots were examined, when but little extension of the cracks and 
no decay had taken place. Two weeks later, after considerable 
rain, a little decay had commenced and some new cracks 
appeared. After another fortnight, i.e., six weeks after mark- 
ing, the roots were lifted and examined, with the following 
results:—Three slits had not increased in size and remained 
sound, 3 had distinctly increased in size yet remained sound, 
6 or 7 new cracks had developed, all of which remained sound. 
In another set of roots on the same plot a series of shallow 
vertical cuts on the top of the crown resembling growth-cracks 
were made with a knife. Examined 6 weeks later, four remained 
sound and two developed into a cankerous wound. 
A similar experiment was performed on plot C (infected soil) 
with the addition of 12 horizontal cuts on the side of the root. 
All these cuts, however, remained sound. It was noted that an 
pa surface attracted slugs, = ae -injury being obvious both 
n growth-cracks and artificial cuts 
Summing up the Kew experiments, it may be said (1) that 
growth-cracks occurred at Kew as in Worcestershire, but they 
were decidedly smaller in size and later in OO re (2) that 
canker followed in a few cases as a result of these or other 
injuries; and (3) that canker was found to is no more frequent 
the plots inoculated with Evesham soil or with diseased roots 
from Evesham than in the ordinary Kew soil. The less ae 
Tt may perhaps be accounted for by the small size e 
his was due to the seed being sown late (nid April) 
saa the soil being a heavy compact silt which had not been 
manured for two years. 
* Experiments carried out by Messrs. ‘cee: at poise for testing the 
effect of manures showed a distinctly larger perce! er than at 
ew. The use of lime proved highly penie aeses Pboth an eae to size of 
roots and reduction of canker. e use of manures me, such as 
Pernvian guano, s of ammonia and pease of sreatgee not 
successful in mitigating the disease. 
