CHAPTER XI. 



RESPIRATION. 



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

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

 esses of animals, is easily demonstrated in several ways. 



221. Simple experiment to demonstrate the evolution of 

 C0 2 during germination. Where there are a number of stu- 

 dents and a number of large cylinders are not 

 at hand, take bottles of a pint capacity and 

 place in the bottom some peas soaked for 12 to 

 24 hours. Cover with a glass plate which has 

 been smeared with vaseline to make a tight 

 joint with the mouth of the bottle. Set aside 

 in a warm place for 24 hours. Then slide 

 the glass plate a little to one side and quickly 

 pour in a little baryta water so that it will run 

 down on the inside of the bottle. Cover the 

 bottle again. Note the precipitate of barium 

 carbonate which demonstrates the presence of 



Fig. 101. t f r 



Test for presence of CO 2 in the bottle. Lower a lighted taper. It 



carbon dioxide in ves- . , , , ... . 



sei with germinating is extinguished because of the great quantity 

 of CO 2 . If flower buds are accessible, place 

 a small handful in each of several jars and treat the same as in 

 the case of the peas. Young growing mushrooms are excellent 

 also for this experiment, and serve to show that respiration takes 

 place in the fungi. 



no 



