56 MINNESOTA BOTANICAL STUDIES. 



The solution was diluted to 12500 cc. and from five to eight 

 drops of ferric chloride were introduced in each jar before 

 using. 



The bell jars used in enclosing the bulbs and shoots had 

 ground edges and were set upon ground glass plates which 

 had been anointed with a preparation composed of vaseline, 

 tallow and resin, to make the connection absolutely air tight. 

 The temperature was kept as constant as possible. 



The pressure of one atmosphere is to be understood where 

 not otherwise stated. 



i. THE INFLUENCE OF GASES AND VAPORS UPON THE GER- 

 MINATION OF SEEDS. 



A. Gases. The gases used were nitrous oxide and oxygen. 

 Seeds of Phaseolus multiflorus and Vicia faba were soaked in 

 water for twenty-four hours and from these were selected ten 

 normal specimens for each experiment. They were then 

 placed on sections of cork, which had previously been soaked 

 in water and introduced into the bell jar under water so as to 

 prevent any air from gaining admittance. Duplicate exper- 

 iments and duplicate controls were set up. The capacity of 

 bell jars was two litres. 



The results obtained with nitrous oxide and oxygen agree 

 with previous experiments in the same line. (Detmer II.) The 

 seed germinated readily in an atmosphere of free oxygen, but 

 failed to do so in an atmosphere of nitrous oxide. The nitrous 

 oxide gas did not kill the seeds, as they afterwards germinated 

 under a bell jar in ordinary air. The N 2 O used here was ob- 

 tained from ammonium nitrate. 



B. Valors. Seeds of Phaseolus mufajftorusiand Vicia faba 

 were placed under bell jars, 4000 cc. capacity, tightly secured 

 to glass plates. Twelve dry seeds of each kind were placed 

 under each bell jar, together with a small glass vial containing 

 accurately measured quantities of the reagent. The seeds 

 were kept under the bell jars for nine days, when they were 

 taken out and each lot planted separately in four-inch pots. 

 The control experiment was treated exactly in the same way as 

 the others with the exception of the omission of the chemicals. 

 The plants were growing side by side and received the same 

 treatment. 



