GENERAL BIOLOGY 



Distilled water, (b) Pasteur's 6 solution without sugar, (c) Det- 

 mer's 7 solution. 



2. Compare growth of peas in (a) Soil sterilized by steam, 

 (b) Soil rich in bacteria, (c) Soil inoculated with Nitrogen- 

 fixing bacteria. 



Describe and explain results. 



3. DEMONSTRATION OF RESPIRATION. 



a. Place germinating seedlings of bean on moist filter paper 

 supported in a closed jar over baryta water. Observe the latter 

 after a day or two. What does the precipitation in the latter 

 indicate ? 



b. Place other germinating seeds in a sealed jar from which 

 oxygen has been removed by any of the following methods: (i) 

 By exhausting air with an air pump, (2) by absorbing oxygen 

 over pyrogallate of potash, (3) by replacing air by hydrogen. 

 Compare growth of such seeds with others growing in jars con- 

 taining atmospheric oxygen. 



What conclusions do you draw from these experiments? 



c. Fill two thermos bottles with (i) Germinating seeds; (2) 

 Similar seeds killed by 5 per cent formalin. Place the bulb of a 

 delicate thermometer in the midst of the seeds and compare the 

 temperature in the two for the two or three days. 



Explain results. 



4. WATER ABSORPTION, MOVEMENT, TRANSPIRATION. 



a. Demonstration of Osmosis. 



Fill a parchment bag with molasses ; in the open end tie a glass 

 tube, and immerse the bag in a jar of warm water. Observe the 

 rise of molasses in the tube. 



Explain. 



b. Plasmolysis. 



Mount filaments of Spirogyra on three slides from the follow- 

 ing solutions: (i) 5 per cent, (2) 10 per cent, (3) 20 per cent 

 cane-sugar solutions. Observe under microscope effects on cell 

 contents. As soon as contents of (2) or (3) begin to shrink re- 

 place solution by tap water and observe results. 



Explain. 



6 See p. 32. 



7 Detmer's solution : Calcium Nitrate, i gram ; Potassium Chloride, .25 

 gram; Potassium Phosphate, .25 gram; Magnesium Sulphate, .25 gram; Dis- 

 tilled water, 1000 cc. 



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