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EXPERIMENT I.—On 18th June, 1881, seven healthy young wheat plants, about 
six inches in height, were infected with the spores of 4cidiwm berberidis, which were 
mixed with water, and freely applied to both surfaces of the leaves, and parti- 
cularly to the angle which the blade forms with the stem. The pots containing 
the infected plants were covered by a large bell glass, and plunged, with great 
care, into the ground. At the same time 18 precisely similar wheat plants, grown 
from the same seed, were placed in the ground in a pot, and covered by a bell 
glass, to be kept as check plants. The cidium was obtained from North Woot- 
ton, distanced 3} miles, and the spores were used for inoculation within two hours 
from the time they were gathered. A number of them were at the same time 
placed upon a drop of water on a glass slide, and kept in a damp atmosphere for 
48 hours, when they were found to have germinated freely, which was proof posi- 
tive of their vitality, and that they had not been injured by removal. Both 
groups of plants were watered from time to time, which was done by raising the 
edge of the bell glass covering them, an inch or two. At the end of 10 days the 
bell glasses were removed, and the plants examined daily. On the 25th day a 
single spot of Uredo was observed upon one of the infected plants; the others all 
remaining free. On the 30th day this leaf was removed and examined, and found 
to be veritable Uredo linearis. On the 32nd day two more of the infected plants 
had Uredo upon them, but it was now found upon the check plants: that is, in 22 
days from the time they were uncovered. On the 43rd day the experiment was 
concluded, when the whole of the seven infected plants had Uredo upon them, as 
well as 16 out of the 18 check plants. 
EXPERIMENT II.—On the 2nd July, three wheat plants, about the same size 
as those used in the previous experiment, were infected with the spores of dei- 
dium berberidis, obtained from the same source, under similar conditions to those 
of the former experiment. Three similar wheat plants, grown from the same seed, 
were kept as a check experiment. Both groups of plants were covered by bell glasses. 
The vitality of the dcidium spores was proved by their germinating freely in 
20 hours. On the 10th day the bell glasses were removed. On the 15th day a 
yellow spot was seen upon one of the infected plants; and on the 17th day all the 
infected plants had undoubted Uredo upon them ; the check plants remaining 
healthy. On the 23rd day the experiment was concluded, and the whole of the 
plants taken up. All three infected plants had abundant Uredo upon them ; but 
the check plants remained free from it. 
EXPERIMENT III.—On the 5th July, two plants of wheat were infected with 
4icidium spores from the same source, and three plants kept as checks ; both were 
covered by bell glasses. The infected plants were, however, kept covered a few days 
longer than the check plants. The Zcidiwm spores germinated freely in 22 hours. 
On the 13th day Uredo appeared upon one of the check plants, and on the 14th 
day upon another ; the infected plants remaining healthy. The experiment was 
terminated on the 3lst day, when both check and infected plants were found to 
have Uredo upon them, 
EXPERIMENT IV.—On the 9th July, one wheat plant was infected with Aei- 
dium spores from the same source, and a similar wheat plant kept as a check 
