in Oats arid Barley. 
409 
Hundreds of spores adhered externally to the oats, the germi- 
nating power of which was tested before they were planted. 
The chemical disinfectants in the first nine experiments 
were mixed in the stated proportions with water. It will 
be observed that No. 10, in which the germinating power of 
spores was not diminished, gave as many blighted ears as the 
undisinfected sample No. 1 ; also that the complete destruc- 
tion of the vitality of the spores in experiments 3, 8, 12, 
14 was followed by a crop without a smutted ear, and that a 
considerable reduction in the vitality of the spores was accom- 
panied by a considerable reduction in the proportion of the 
smutted ears in the crop (Nos. 2, 5, 9, 13). 
In one of the experiments, however (No. 2), the reduction 
of the smutted ears in the crop was considerably greater (from 
36 to ^ per cent.) than would have been anticipated from the 
moderate reduction in the vitality of the spores (from 20 to 5 per 
cent.). Provided the disease in the crop does not arise from a 
mycelium in the seed, which is, I think, almost out of the ques- 
tion, this discrepancy may be accounted for by the fact that the 
sulphate of copper, which was the agent employed, not only 
kills a part of the spores, but poisons a certain proportion of the 
remainder. In this the action of sulphate of copper differs from 
the other substances employed. Many of the seeds germinated 
incompletely by emitting the embryo only, so that the young 
plants remained for two or three weeks rootless in the ground. It 
is possible that in Experiment 2 the sulphate of copper had only 
killed three-fourths of the spores, yet the other fourth was so 
enfeebled by its action that the spores were incapable of sending 
a mycelium into the young plant. 
Respecting the action of the above methods of dressing the 
seed-corn the following remarks suggest themselves : — 
Sulphate of Copper. — A watery solution containing only a 
\ per cent, of this salt reduced the number of smutted ears to 
such an extent (1 : 72) that it might be considered practically 
sufficient. But part of the seed-corn was killed, and the crop 
suffered not inconsiderably. With a one per cent, solution 
about three-fourths of the seed-corn was killed, and a large 
number of the young plants remained without rootlets for two or 
three weeks. This lot was still green when all the others were 
almost ripe. 
Sulphate of Copper and Lime. — The effect of a one per cent, 
solution of sulphate of copper, followed twelve hours afterwards 
with lime, was very remarkable. The addition of lime saved a 
considerable portion of the seed from destruction, though not all, 
P9 that the crop was almost as good as that from No. 1 (the 
