134 



BOTANICAL GAZETTE 



niBRl'AKY 



Material was weighed, then ground in a mortar with a small amount 

 of quartz sand and a knife point of calcium carbonate for exactly 

 2 minutes. This emulsion was then washed with the aid of 10 cc. 

 of distilled water into a 200 cc. wide-mouthed bottle. The latter 

 was then corked and plunged into a water bath kept at 25 C. 

 The commercial form of Oakland dioxygen was used at all times. 

 This dioxygen gives an acid reaction. To neutralize the acidity 

 a small excess of calcium carbonate is added to the dioxygen just 



Fig. 2. — Respiratory curve for first 14 days of germination in dark at 25 C; 

 time of germination in days plotted on abscissae and mg. of C0 2 given off in 24 hours 

 per gm. of dry weight plotted on ordinates. 



before using. If the acidity is not corrected, the catalase activity 

 is reduced approximately one-half. A small separatory funnel 

 inserted in the cork of the bottle holds the dioxygen. The latter 

 is run into the ground tissue when the dioxygen and pulp have 

 reached the same temperature as the water bath. The material 

 is then shaken uniformly for 10 minutes by means of a small motor. 

 The oxygen liberated is collected over water at atmospheric pres- 

 sure in a 100 cc. burette. Table II shows the catalase activity 

 at various times during desiccation and the early stages of 

 germination. 



