58 MINNESOTA BOTANICAL STUDIES. 



trary in series I and II it seems to have hastened the time of the 

 flowering by three to four days. Vicia faba is more suscep- 

 tible to ammonia vapors than Phaseolus multiflorus. As in the 

 case of Phaseolus multiflorus the leaves were darker than in the 

 control. The measurements given in the table above represent 

 the average growth of shoot of twelve plants. 



2. THE INFLUENCE OF GASES AND VAPORS UPON SEEDLINGS. 



A. Gases. Nitrous oxide of oxygen and seedling of Zca 

 mais and Phaseolus multiflorus were employed in these experi- 

 ments. The seedlings were carefully measured and placed 

 under bell jars while full of water which was displaced by the 

 gases. 



The following quantities of gases were used : 400 cc. of ni- 

 trous oxide in 2000 cc. of air and an atmosphere of free nitrous 

 oxide ; 400 cc. of oxygen in 2000 cc. of air and an atmosphere 

 of free oxygen. These were set up in duplicates and the con- 

 trol was also in duplicate. The results of the experiments 

 showed an increase in growth for seedlings in the two oxygen 

 experiments and also for the nitrous oxide experiment in which 

 400 cc. in 2000 cc. of air was used. The average increase in 

 the two oxygen experiments and the control for 24 hours 

 was little less than 8 mm. The seedlings in the atmosphere of 

 free oxygen did not average as much as those in the partial at- 

 mosphere of oxygen. The average was 5 mm. 



The seedlings in the experiments in which 400 cc. in 2000 

 cc. of air was used showed a slight increase in growth over 

 the control, amounting on an average to 3 mm. The seedlings in 

 an atmosphere of free nitrous oxide did not make any growth, 

 but were alive when taken from the bell jar. The temperature 

 during the time the experiments were running varied from 21- 

 23 C. 



B. Vapors. The following chemicals were used : Ether, 

 chloroform, carbon bisulphide, alcohol and ammonia. Seeds 

 of Zea mais were germinated in clean saw-dust and when the 

 roots had attained a length of 15 to 20 mm. and the plumule 

 from 10 to 15 mm. a uniform lot was selected for the experi- 

 ments. The roots and shoots were carefully measured and 

 marked with India ink. The seedlings were next placed under 

 the bell jars of 2000 cc. capacity upon moist saw-dust. The 

 chemicals were accurately measured out and put into small glass 



