196 Bailey. — Puccinia malvacearum and the My coplasm Theory. 
Finally, as regards the pot-controls which were kept throughout in the 
greenhouse: these, as shown above, failed to show any rust until artificially 
inoculated. They were much attacked by various pests, and their growth 
much stunted in consequence. The amount of rust present on them 
increased slowly up till December 18, 1914, but never exceeded more than 
a few pustules per plant. After that date the amount of infection decreased, 
until in March 1915 only one plant remained infected. 
Summary of Results of Experiment 1. 
The experimental plants were kept under observation for a protracted 
period, far beyond that claimed by Eriksson as necessary for the develop- 
ment of c primary infection ’. 
Eriksson’s period is three months from the time of sowing, when 
growth is continuous as in this case. In this experiment the first appearance 
of rust was 10J months after sowing. 
The observed deterioration of rubber connexions eventually admitted 
of outside infection. 
In all, six plants out of ten in the globes developed disease. In three 
of these instances attempts — apparently unsuccessful — at inoculation had 
been made, and it is possible that the eventual infection was due to this 
rather than to contamination from outside. In all six the infection, to 
begin with, presented a ‘ secondary ’ rather than a ‘ primary ’ facies. It 
soon developed an intensity equal to that of 4 primary infection ’. One of the 
six plants cut down to the root and allowed to sprout again showed no 
recrudescence although watched for six months. 
The results indicate strongly that the protected plants did not suffer 
from ‘ primary infection though raised from seed in which, according to 
Eriksson’s views, ‘ primary infection ’ would have been anticipated. 
The control plants also in no case gave the phenomena of f primary 
infection ’, though some, at least, were raised from seed taken from plants 
which were known to have been heavily infected. 
Certain of the controls, when once the disease had made a start, 
developed the rust with a prodigality equal to that of ‘ primary infection ’. 
Others remained only slightly infected to the end. The comparative 
immunity of these latter plants may be attributed with little hesitation to 
the stunting effects of red spider. 
The behaviour of these particular controls contrasts strongly with that 
of the plants in globes. Both series of plants were slow to show infection 
at all, but whereas the controls, stunted by insect attacks, showed little 
tendency to a further development of the fungus, the plants in globes 
succumbed with a rapidity greater than any noted under the most favourable 
conditions outside. 
1 
