RES P IRA TION. 



101 



Starch formation or 

 Photosynthesis. 



Respiration. 



Comparison of respiration and starch formation. 



Carbon dioxide is taken in by the plant and oxygen 

 is liberated. 



Starch is formed as a result of the metabolism, or 

 chemical change. 



The process takes place only in green plants, and in 

 the green parts of plants, that is, in the presence 

 of the chlorophyll. (Exception in purple bacte- 

 rium.) 



The process only takes place under the influence oi 

 sunlight. 



It is a building-up process, because new plant sub- 

 stance is formed. 



Oxygen is taken in by the plant and carbon dioxide 

 is liberated. 



Carbon dioxide is formed as a result of the meta- 

 bolism, or chemical change. 



The process takes place in all plants whether they 

 possess chlorophyll or not (exceptions in anaerobic 

 bacteria). 



The process takes place in the dark as well as in 

 the sunlight. 



It is a breaking-down process, because combustion 

 of plant substance occurs. 



Material and apparatus. Peas soaked for 24 hours in cold water (enough 

 for class and for demonstration). 



Peas germinated, and with roots about 2Qmm long. A few should be 

 started 4 or 5 days in advance of the time they are wanted. 



Wide-mouthed bottles, or cylinders, with glass plates and vaseline, to 

 close them, or corks (glass plates are better). 



Tapers, or soft wood splinters for flaming. 



Baryta water (saturated solution of barium hydrate in water) in tightly 

 stoppered bottle. 



Watch glasses for baryta water. 



For demonstration 27: glass cylinder about 35;/high by $cm in diameter ; 

 perforated rubbor cork to fit very tightly ; S manometer made from glass 

 tubing about 6mm diameter ; mercury ; small glass jar and vial ; support 

 as indicated in demonstration 27 ; tome sticks of caustic potash ; baryta 

 water ; a stout needle. 



For demonstration 28: potted plant ; bell jar to cover ; baryta water. 



