148 Wisconsin Academy of Sciences, Arts, and Letters. 
above. Seedlings were left uninoculated in each experiment to 
serve as controls. 
With one exception none of the seedlings or leaves inoculated 
became infected, although the experiments were continued from 
eight to fifteen days. The controls also remained free from the 
mildew. In one experiment, leaves of blue grass in a Petri dish 
were inoculated, and when examined after five days were found 
badly infected with the mildew. The pot containing the blue 
grass from which the leaves were taken for the experiment was 
then examined and it was found that the grass had, in some 
way, become infected with the mildew. Consequently there was 
no evidence in this experiment that the rye mildew could infect 
the blue grass. In the other eleven experiments in which blue 
grass was inoculated with spores from rye no infection occurred. 
On the other hand the rye leaves and seedlings inoculated 
with conidia from rye in connection with the above experiments 
in every case except two had infected areas after about five 
days. During the same interval of time, none of the control & 
were infected. The seedlings were examined from day to day, 
the controls especially being watched closely. Patches of myce¬ 
lium bearing conidia appeared on several of them eight or nine 
days after the experiment was started. Evidently some of the 
conidia that were first produced on the inoculated seedlings had 
fallen upon the controls and then germinated, producing infec¬ 
tion. This infection occurred only after a period of time equal 
to that which had elapsed between inoculation and the first ap¬ 
pearance of conidia on the inoculated leaves. The mildew was 
also much more widely spread over the inoculated seedlings 
when the controls became infected. 
A further interesting experiment was made to show that the 
spores from rye would not infect the other cereals. On March 
25th, seeds of the four cereals, wheat, rye, oats and barley, were 
sown in a large pot, about fifteen inches in diameter, one kind 
of seed in each quadrant of the surface. Shortly after the 
young seedlings came up they were all inoculated with conidia 
from rye. The seedlings were left growing until about the 
middle of July when they had matured, producing normal ker¬ 
nels. The rye seedlings became infected about four days after 
