294 



BOTANICAL GAZETTE 



[APRIL 



that the neutrahzation of dioxygen or the addition of CaCOj is 



sufficient to eliminate any error due to the acidity of the reagent 



or the meal. 



TABLE VIII 



Effect of reaction of solution upon amount of oxygen liberated 



FROM DIOXYGEN BY Tilia SEEDS 



Oxidase activity. — The determinations of oxidase activity 

 were made on dry, after-ripened, and germinating seeds in 

 Bunzell's (4) simplified apparatus with pyrogallol as the reagent. 

 The material used, except in the case of the dried seeds, had been 

 after-ripened at 0-2° C. for 140 days and then kept at 10-12° C. 

 until a large percentage of the seeds had begun to germinate. 

 After being dried in a vacuum over lime for 3 days at room tempera- 

 ture the seeds were ground in a mortar and the determinations 

 made on 0.02 gm. of meal. Table IX shows the readings in centi- 

 meters of mercury after 3 hours and after 20.5 hours. 



TABLE IX 



Oxidase activity of dry, after-ripened, and germinating 



SEEDS of Tilia 



During the experiment the temperature averaged 31.3° C. with 

 a variation of =^=0.1 of a degree. Variations in the volume of air 

 in the tubes due to this slight variation in temperature have been 

 corrected by means of check tubes containing water only. The 



