I'AKT IV 

 PHYSIOLOGY OF NYrumox ( Ixt i.rmxv, CIRC n..vnox 



AM" Kl'.Sl'IK. \TIOX ) 



./. METABOLISM 



A verv important division of metabolism (the action ot cnxyino i 

 i> already 

 considered. 



ha- already been >tudied. Certain general features remain to be 



I. HOLOPHYTIC METAB< LISM. 



_'4<>. O.vytjcn formation. 1'lace in a tot-tube with clean water 

 a healthy branch of Elodea (or some other water plant that has 

 not finely divided leaves). Do not use water from the hydrant, for 

 this contains too much air; use if possible water in which the plants 

 a i\- found, or other water that has stood for a time in tanks, and 

 be careful not to get any bubbles of air in the tube. Invert the 

 test-tube in a vessel of the same water. Place in a bright light, 

 where the direct rays of the sun reach it. 



At the same time prepare another experiment, in exactly the same 

 way. but place this in complete darkness. 



Try the same experiment, but using water that has been boiled 

 thoroughly and cooled (|tiicklv without disturbance. \\ash the 

 plant in this water before placing in the tube. I Mace in sunlight 

 as before. Any difference from above result : Explain. 



Allow the three experiments to stand for some hours or for a day, 

 if Decenary. In which one are bubbles of gas produced? If in all 

 three, which -hows the larger |uaiitity? Test for oxygen by the 

 >park test. 



j |~. I'liotosvnthcsis in\ plants. Kxamine Spimgyra lilameiit- 

 that have' been well exposed to light. Study the chlorophyll band-. 

 Sketch. Then run under the cover-glass of a second preparation a 

 little iodine -ulutioii and examine. Compare carefully with the un- 

 treated preparation. .Vote the distribution ot March. Examine 

 similarly filament- that have been kept in dark some day-. Xote any 

 diff. Ti-nrr ' Kxplain. 



7- 



