36 ON THE RELATIONSHIP OF jECIDIUM BERBERIDIS, PERS., 
numerous, can per se be taken as conclusive. It was in the hope 
that reliable evidence one way or the other could be obtained, that 
the following series of experiments have been, during the past 
five months, carried on, and which I now venture to place before 
you : — 
Experiment I. — On 18th June, 1881, seven healthy young 
wheat plants, about 6 inches in height, were infected with the 
spores of JEcidium berberidis , which were mixed with water, and 
freely applied to both surfaces of the leaves, and particularly 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 JEcidium was obtained from North Wootton, 
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 positive 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 in- 
fected with the spores of jEcidium berberidis , obtained from the 
same source, under similar conditions to those of the former experi- 
ment. 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 Mcidium spores were 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 con- 
cluded, and the whole ot the plants taken up. All three infected 
plants had abundant Uredo upon them ; but the check plants re- 
mained free from it. 
Experiment III. — On the 5th July two plants of wheat were 
