XIV. RESPIRATION 



A. Anaerobic Respiration: 



Experiment 36. To illustrate anaerobic respiration. 



1. Remove the seed-coats from three or four pea seeds 

 that have soaked in water over night. 



2. Fill a large glass test-tube with mercury, and 

 invert it in a bath of mercury. 



3. Place the pea Seeds under the mouth of the inverted 

 test-tube, and allow them to float to the top. Use 

 every possible precaution to prevent air being car- 

 ried up with the peas. Can the presence of air 

 be entirely prevented? 



4. Securely fasten the test-tube in the inverted posi- 

 tion, with its mouth under the surface of the mer- 

 cury in the bath, and during the next twenty-four 

 to forty-eight hours observe the formation of 

 gas, which replaces the mercury around the seeds. 



5. Now introduce in to the test-tube with the pea seeds 

 a small piece of potassium hydroxide. If the gas 

 given off by the seeds is COz it will be absorbed by 

 the potassium hydroxide, and the mercury will rise 

 in the tube. 



6. Do these seeds respire under strictly anaerobic con- 

 ditions? Discuss, iny our note-book, all the pros 

 and cons, and endeavor to make a clear statement 

 of just what this Experiment does and does not 

 demonstrate. 



B. Aerobic Respiration: 



Experiment 37. To demonstrate what exchange of 

 gases accompanies the aerobic respiration of a living 

 plant. 



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