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PHYSIOLOGICAL PROCESSES IN PLANTS 



tents of an egg through a small hole at one end ; place the shell 

 in a tumbler and cover with weak hydrochloric acid or vinegar. 

 (Fill the shell with water so that it will sink.) When the 

 shell is dissolved away, fasten the membrane to a J-inch glass 

 tube as shown in Figure 17, by using a few turns of string 

 or a rubber band. Place it under water and blow gently in the 



FIG. 17. Experiments to show osmosis. 



tube to see if there are any leaks. If there are none, pour into 

 the tube enough strong sirup (made of glucose and water) to 

 fill it to a point a little above the membrane. Submerge in 

 water, as in Figure 17, so that the two liquids are at a level. 

 The membrane may well represent a root hair, or cell, and the 

 glass tube one of the tubes of a fibrovascular bundle of a root. 



The experiment may be varied by setting it up as in 

 Hunter, Elements of Biology, page 89. In many respects this 

 is preferable, as the white of an egg is much like protoplasm 

 or the living matter in cells. 



Artificial root hairs may also be made by pouring a small 

 amount of celloidin or of collodion in a i-dram tube-vial and 

 tipping it about so that the contents are hardened into a thin 



