372 BOTANICAL GAZETTE [NOVEMBER 
The charts do not show the results obtained at low temperatures, 
but in every instance cultures were placed at 5° and 10°. Spores 
kept for two days in a particular toxic solution at a temperature so 
cold that it inhibited their germination gave, upon removal to the 
room temperature, a germination and development that was but 
little inferior to that obtained from the fresh spores under like condi- 
tions of medium and temperature. Spores inhibited at a tempera- 
ture that did not prevent germination were more greatly injured. 
Spores of Mucor gave fair growth in n/32 H,SO, and n/32 HNO, 
after removal from 5°, but after removal from 10° did not germinate. 
Sterigmatocystis spores in n/16 HNO, grew almost as well after 
removal from 10° as from 5°, but in the cultures removed from 15° 
(a temperature not inhibiting germination in the control) no germi- 
nation was obtained. 
A comparison of the curves obtained with the different chemicals 
shows that those for weak concentrations of HNO, do not drop so 
rapidly at high temperatures as the curves for weak solutions of the 
other toxic agents. : 
In order to obtain additional information in regard to the signifi- 
cance of the results secured with the cells, a series of flask cultures 
was made. In every instance 25°° of the given solution were placed 
ina 100° flask, These flasks were sterilized after the introduction of 
the solution. The effect of the toxic agent was determined by taking 
the dry weight of the fungous growth at the end of the given time. 
With the exception of n/64 CuSO,, duplicate cultures were made 
and the average weight used in estimating the effect. Flask cultures 
were made of Mucor, Penicillium, and Sterigmatocystis. The results 
obtained from cell cultures were used as a basis in determining 
what strengths of the toxic agents should be used in the flasks. So 
much greater concentration was required to give injury in flask cul- 
tures than in cells that no definite results were obtained with Mucor 
and Penicillium. Also it was found that Penicillium would not grow 
in flask cultures placed at 30° C., a temperature at which the fungus 
grew well in the control cell cultures. 
In the series with Sterigmatocystis the air in the incubator ™ 
dry, while that in the refrigerator was kept damp by the melting ys 
It was feared that the evaporation from the flasks at 25° and 30 
