No. 33] 361 
oculation is made on the fruit, the most successful trials being with 
fruit about two-thirds grown, the earliest made, showing a develop- 
ment of the disease of astonishing virulence. Frnit of full size and 
on the point of ripening took the infection slowly, and in a much 
milder form. . 
Another element affecting the virulence of the disease was brought 
into notice while working on the fruit. This made prominent the 
fact that the more succulent the tissues the more strongly manifested 
became the disease. It was well shown in experiments 71 to 75 on 
green fruit of Bartlett pear. These were begun on July 24, and 
not again looked at until July 30, when they were found to have 
uniformly developed a wholly unexpected form of the malady. A 
circular spot three-fourths of an inch across had taken on the brown 
color of rotting fruit: At the center of this spot, and immediately 
J UNE-BERRY. 
No. of Part Source - Days of 
experiment. treated of virus. incubation. 
Demme. Sie Bld vie eis oad 5 Stem. Pear. - 6 
VES ODORS Cae iafrepiel aici os ce AS ic 
OU ees 6d ae es a - 
RU Gi ik aisle lel lea aa 62a! as + 
2.9. 250% bs fa ele oe ees fe : 
I iano bed y a) x iene neelnti us Apple. 
MMS to Pais a'n) aha. daw gio ele Fe # 
INERT, 22 (heals fe) wie oS 20 eel - Quince. 5 
surrounding the wound made by the inoculation, the tissues had 
sunken somewhat, while from the slightly enlarged wound there 
flowed an abundant yellowish pus that ran down the surface of the 
pear and dripped on the ground. It was an ulcer of quite as sick- 
ening appearance as if on animal flesh. ‘The pears were all but one 
removed at. once from the tree and placed under bell jars in the 
laboratory. The remaining one was left three days longer, and not 
showing any additional features of the disease was then removed. 
Upon cutting open one of the pears almost the whole interior was 
found to be diseased and brown. On August 4 two pears lying un- 
molested in the bell jars had become so thoroughly rotten with the 
disease that several new abscesses had broken out, from which as well as 
from the original wound there was a copious suppuration. The 
instances which follow are in: marked contrast. On July 26 a 
Flemish Beauty pear was inoculated (exper. 87) which only produced 
asingle large drop of exudation from the wound, much too thick to 
flow. Several Baldwin apples inoculated July 31 partly gave no exuda- 
tion and partly (exper. 100 and 113) barely as much as the Flemish 
Beauty pear. A number of quince fruits were inoculated (exper. 
66 to 70) at the same time as the Bartlett pears but gave no exuda- 
tion at all. The different results are in the main explainable on the 
ground of the varying succulency of the different fruits. The va- 
