CHAPTER IX. 



RESPI RATION 



126. One of the life processes in plants which is extremely 

 interesting, and which is exactly the same as one of the life pro- 

 cesses of animals, is easily demonstrated in several ways. 



127. Oxygen from the air consumed during germination of 

 seeds. — Let us take a half pint or a pint of peas, tie them in a 



bag or loose cloth, soak them in warm water 

 for 10 or 12 hours, or in cool water for about 

 24 hours. Drain off the surplus water and lower 

 the cloth with the peas in a tall glass cylinder 

 which holds 1 to 2 liters. This should be 

 covered with a glass plate after vaseline has 

 been smeared on the edges of the cylinder to 

 make the vessel air tight. Set aside in a warm 

 room for about 12 hours. Now lower alighted 

 taper or short candle into the vessel after having 

 carefully removed the cover. The flame is 

 Fig- 47- extinguished. This indicates that there is no 



Test for presence of 

 carbon dioxide in vessel oxygen in the Vessel, 

 with germinating peas. J 



(Sachs.) 128. Carbon dioxide given off during ger- 



mination. — Now let us lower a small vessel containing lime water 

 into it. Very soon, almost immediately, there is formed on the 

 surface of the lime water a film. The film formed under these 

 conditions is known to be carbonate of lime, which is formed by 

 the union of carbon dioxide in the vessel with the iime in the 

 water. (Note. Where there are a number of students and large 

 vessels are not at hand, bottles of a pint capacity and a smaller 

 number of peas will answer. ) 



54 



