Blister Canker 
15 
Five others were inoculated and placed in cylinders with 
ground glass stoppers which prevented evaporation. One sec- 
tion of each was examined each week. The first examination 
showed little growth in either case. The second week the 
sections from the cotton-plugged cylinder showed the most 
vigorous growth. The third week the hyphae had advanced 
in one of the sections sterilized with mercuric chloride in the 
cotton-stoppered cylinder 1% inches and in the one sterilized 
by steam 214 inches. In the sections where no evaporation 
was permitted the one sterilized with steam showed an ad- 
vance of 11/4 inches in three weeks and the one sterilized with 
mercuric chloride 1 inch. After this time practically no 
growth was made in sections sterilized with mercuric chloride 
and allowed to dry. A growth of 314 inches was found the 
fifth week in the steamed section which was allowed to dry. 
Of the sections not allowed to dry out the one steamed, exam- 
ined the fifth week, showed a growth of 2% inches while the 
one sterilized with mercuric chloride showed only II/2 inches. 
In the sections sterilized with mercuric chloride only the 
heartwood was invaded, but in those sterilized with steam 
even the bark was invaded. In all cases, but more noticeably 
where the wood was steamed, a dark brown slimy liquid 
exuded from the wood. This remained in the bottom of the 
tightly closed cylinders but soon dried up in those plugged 
with cotton. 
Sections of branches were then dried by heat until 10 and 
20 per cent of water respectively had been lost, and enclosed in 
cylinders as above. Growth was noted in only one case where 
the cylinders were plugged with cotton and only slight growth 
was secured where the cylinders were tightly closed. 
Twelve branches one-half inch in diameter and bearing 
leaves were inoculated in one-year-old wood and placed with 
the cut ends in water. At the end of the sixth day the myce- 
lium had grown above the inoculation an average of 414, 
inches. Branches which were inoculated and not placed in 
water showed practically no growth. 
EXPERIMENTAL. INFECTION 
In 1914 a series of inoculations were planned in order to 
secure definite data on the manner in which the disease is most 
readily disseminated, how infection occurs, the rate of prog- 
ress of the disease after infection occurs, varietal resistance 
and control measures. Actual work in the field was begun in 
May of 1915, altho inoculations had been made on trees in the 
