364 ‘BOTANICAL GAZETTE [NOVEMBER - 
and time of exposure were determined, such as would give the greatest 
contrast in the results obtained at the various temperatures. 
DATA AND DISCUSSION. 
In order to put the results obtained in a form as concise as pos- 
sible, charts 1a—-12c have been prepared, and the greater part of the 
data obtained is expressed in these by means of curves. 
In charts 1a to 1o¢ inclusive, the abscissae indicate the tempera- 
tures at which the fungus was kept in culture, and the ordinates 
show the per cent, of germination at these temperatures. All the 
points indicating per cent. of germination at the various temperatures 
for a particular toxic solution are joined by solid or broken lines; 
the strength of the toxic solution used is shown by the fraction placed 
on or near the particular curve. For a further illustration of the 
meaning of these charts, the curves in chart 2a may be considered. 
These represent the data secured by using CuSO, with Monilia. With 
an 7/16 solution no germination was obtained at 25° and 30°; but 
at 15°, 12 per cent, of the spores germinated; at 10°, 30 per cent.; 
and at 5°, 49 per cent. 
In charts 1a to sc inclusive the results were obtained by exposing 
the spores for twenty-four hours at the various temperatures in the 
toxic solution indicated and then transferring them as previously 
described. The charts are based entirely upon the data secured on 
the first and second days after transferring. The solid lines indicate 
the total germination at the end of the second day. The broken 
lines show the per cent. of germination twenty-four hours after trans- 
fering, Where the record of germination was the same for the two 
days only the solid line is used, It will be noticed that only in 4 
very few instances did spores germinate on the second day. 
It is readily seen that in most cases the deleterious action of the 
toxic agents increased very rapidly with the rise in temperature. 
A comparison of the charts for the various fungi indicates that there 
are some differences in reactions worthy of special note. Thus, 
there is a marked drop between 5° and 10° in the germination curves 
for Botrytis and Monilia, but for no other fungus. With Penicillium 
the fall comes either between 10° and 15° or between 15° and 20°, 
while with Mucor and Sterigmatocystis the downward curves begin 
