192 Bailey . — Puccinia malvacearum and the My coplasm Theory . 
To test whether the conditions were entirely inimical to the growth of 
the fungus, a bunch of heavily infected hollyhock leaves was shaken in all 
parts of the greenhouse. Seventeen days later, as the result of this, six of 
the pot-controls showed one pustule each. In five cases out of six this 
pustule appeared on a fully-developed leaf ; in the remaining one case it i 
occurred on a young leaf. The plants in the globes remained unaffected. 
The plants in pots, standing in the open, were also examined on this j 
date (Sept. 22) and were found to show the beginnings of infection ; 60 per 
cent, showed a few pustules, almost entirely on the middle-aged, fully 
expanded leaves. 
The experiment having now run so long (10J months), it was found 
that the rubber-tissue between the cork and the neck of the globes had 
perished, and the apparatus could no longer be relied on effectively to 
exclude air-borne spores. 
It was decided, however, not to replace the perished rubber, but to keep 
the apparatus running whilst certain inoculation experiments were tried. 
No observations were made on the plants in the globes during the next 
month, with the exception of one which was inoculated on September 29 
and again on October 6 by spraying it with a suspension of germinated 
rust-spores. 
These spores had been germinated at the bottom of a dish of sterile 
tap- water and were examined before they were sprayed on to the plant. 
In all cases, as might be expected, they had germinated in the form of 
‘ oidia ’. The results of both these inoculations were negative. 
On October 28 the plants in the globes were again carefully examined, 
and it was found that in two cases plants were infected with rust. Neither 
of these two plants had been inoculated, and the inference is that they had 
been infected by air-borne spores owing to the faults which had developed 
in the apparatus as described above. 
In both these cases the globes were removed, and the plants cut off at 
the crown and carefully examined. 
The results of this examination are important, as they confirm the 
opinion that the infection was an external one, and not a manifestation of 
‘ primary infection The fact that the pustules were of various ages shows 
that the disease had been running its course for some time before the plants 
were examined. 
In the following table, c G.G. 2 ’ and ‘ G.G. 3 ’ are the reference 
numbers of these cultures, and the leaves are in each case numbered from 
1 upwards, starting with the oldest. 
