8 



percentage results it would be necessary to duplicate the 

 experiments to an extent impracticable under the circum- 

 stances governing work in the laboratory where 225 students 

 are conducting two or three experiments each. 



Experiment 5. — To demonstrate that dry wheat may be 

 stored for some time in an atmosphere of nitrogen gas without 

 impairing the vitality of the seed. 



Method. — Small quantities of wheat harvested in 1917 

 were placed in three bottles — A, B, and C, respectively. In 

 each bottle were placed two small tubes, one containing lime- 

 water and the other an aqueous solution of pyrogallic acid. 

 The bottles were then carefully sealed. The lime-water 

 absorbed the C0 2 , the evidence being the formation of a crust 

 of carbonate of lime within the tube containing the lime- 

 water. The aqueous solution of pyrogallic acid absorbed the 

 oxygen contained in the bottle, evidence of the absorption 

 being the brown discolouration of the otherwise perfectly 

 clear liquid. 



Test (1). — The grain from bottle A grew well when 

 planted on damp soil under glass. Immersion in practically 

 pure nitrogen for fourteen days did not seem to produce any 

 bad effects. 



Test (2). — At the end of twenty -eight days the grain from 

 bottle B was planted on damp soil under glass. It germ- 

 inated freely. 



Test (8). — Through an accident the bottle was broken 

 and the grain lost before its vitality could be tested. A later 

 experiment demonstrated that dry wheat enclosed in an 

 atmosphere of nearly pure nitrogen can retain its vitality for 

 a period of 104 days, but will not survive an immersion in 

 nitrogen for more than 143 days. 



Experiment 6. — To demonstrate the behaviour of wet 

 grain stored in an air-tight receptacle. 



Method. — A small quantity of wheat harvested in 1917 

 was soaked in water for about twelve hours. It was then 

 drained of free water, and sealed in a bottle having a few 

 layers of wet blotting-paper at the bottom. 



Result. — The grain germinated and grew freely until the 

 plumule became about five-eighths of an inch long and the 

 radicle carrying root-hairs had grown to a length of three- 

 quarters of an inch. At this stage of growth further develop- 

 ment ceased. No chlorophyll was developed in the plumules, 

 although they were exposed to light. The plants quickly 

 perished. 



Experiment 7. — To demonstrate the visible effects of 

 C0 2 on wet wheat enclosed in an air-tight receptacle. 



