370 BOTANICAL GAZETTE [NOVEMBER 
at 15° or 20°. This variation may be the result of using solutions 
that were, without regard to temperature, more injurious to some of 
the fungi than to others; but strong concentrations, such as n/4 and 
n/8 HNO,, when used with Mucor and Sterigmatocystis, have not 
given the rise in the curves from 10° to 5° that has been repeatedly 
obtained with Botrytis and Monilia. It should be noted that these 
last two fungi are not only the ones that are most greatly injured by 
the toxic agents, but also are those that require the least stimulus 
for germination. Duccar (10) found that both Botrytis and Monilia 
germinated readily in distilled water, but that Sterigmatocystis and 
Penicillium did not germinate. 
There is also a remarkable agreement in the minimum tempera- 
ture for the germination of a particular fungus under certain condi- 
tions and the location of the fall in its germination curve. Botrytis 
and Monilia not only show the greatest increase in toxic effect on 
passing from 5° to 10°, but they are also the only ones that had 
germinated in the control cultures at 10° by the end of one day. With 
Penicillium the CuSO, and HNO, curves show a tendency to drop 
between 10° and 15°, while in the H,SO, curves the fall comes beyond 
15°. Along with these data should be noted the fact that the control 
with the H,SO, cultures gave no germination in one day, while those 
with the HNO, and CuSO , cultures had germinated in this time. 
This variation in the controls was probably due to a slight change 1n 
the temperature of the refrigerator, together with the fact that 1 a 
approaches the lower limit of temperature for obtaining the germina- 
tion of Penicillium in one day (WIESNER 13). Mucor gave no germl- 
nation the first day in the controls at 15°, with the exception of about 
14 per cent. with the CuSO, series, and Sterigmatocystis in no instance 
germinated in one day at this temperature. As has been already 
mentioned, the curves for these fungi fall between 15° and 20° or at 
a higher temperature. From these facts it is seen that the spores 
exposed to a harmful agent and at the same time inhibited by cold 
have not been greatly injured. g 
In the cultures from which the data in charts 6a to roc inclusive 
were obtained, the spores were in no instance transferred. The cells 
in the CuSO, series remained at the temperature indicated for four 
days; those with the acids were removed at the end of two days. 
