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glasses were never touched until the plants were large enough to infect. On the 
20th August six were inoculated with cidium spores from Narborough. <A few 
days later, purposely choosing a day when there was no wind, the check plants 
were reduced to six. The bell glasses were not again removed until the 20th day, 
when both patches were rapidly but thoroughly examined and found free from 
Uredo. The glasses were replaced, and the plants re-examined on the 30th day. 
These were then finally removed and the plants thoroughly examined, but no trace 
of Uredo found upon either the infected nor upon the check plants. 
The result of these 13 experiments may be thus summarised :— 
Seventy-eight wheat plants were infected with the spores of deidium berber- 
idis and 98 similar wheat plants kept as check plants against them. Of the in- 
fected plants 76 per cent. developed Uredo in an average of 24°4 days. While in 
the same period 70 per cent. of the uninfected plants became spontaneously at- 
tacked by Uredo. One experiment only (No. 2) out of the 13 was wholly in favour 
of the theory, and that lasted only 23 days. Still six per cent. more of the in- 
fected plants took the Uredo than of the uninfected. This is a very small portion, 
far too small in my humble opinion to constitute convincing evidence. I believe, 
however, that it can be accounted for by my own negligence in not thoroughly 
cleaning the bell glasses before using them to cover fresh plants. Had the last 
experiment (No. 18), however, proved favourable to the theory I should have re- 
garded it as being much more worthy of acceptation than I can now do. Itis 
only after much patient work and careful consideration that I felt myself bound 
to differ from the eminent botanists abroad who do accept the hetereecism of 
Puccinia graminis as established beyond question. 
There are two other experiments not included in the above thirteen which 
were performed by me, that I think worthy of notice. 
Experiment No. 36.—On the 2nd August, one oat plant, with 10 leaves upon 
it, was inoculated with Zcidiwm berberidis spores. A very large quantity of ripe 
Alcidium spores was used—on the 15th day Uredo appeared upon the oat plant. 
On the 9th September (38th day) these Uredo spores were examined and found 
to be the Uredo of Puccinia coronata Corda. Now had this experiment been 
carelessly performed the inference would have been that the cidiwm spores had 
produced the Uredo of P. graminis. 
ExpErIMENT No. 40.—Six wheat plants were infected with the spores of Uredo 
linearis at 4 p.m. on the 18th August. On the 24th they all were simultaneously 
affected with Uredo, showing that the Uredo had reproduced itself in 11 days. 
