Roots. 29 



made a good growth, remove the soil from the pot and 

 note the effect of the roots on the surface of the marble or 

 shell. Does this teach anything as to the possible effect 

 of the roots on the limestone constituents of the soil ? 



45. To demonstrate the force with which roots absorb 

 water from the soil, cut a groove in the form of a circle 

 about two centimeters in diameter, by means of the edge 

 of a three-cornered file, at the large end of a hen's egg. 

 Carefully remove the shell within the circle, guarding 

 against puncturing the delicate skin. File with the flat 

 face of the file at the small end of the egg until a thin area 

 about four millimeters in diameter has been produced, 

 make a small hole in the shell at the thin place, and blow 

 out the contents by means of a glass tube drawn out in a 

 flame to a fine point. In this "operation the tube must not 

 entirely close the opening in the shell. Set the egg, large 

 end down, in the mouth of a wide-mouth bottle which has 

 been filled with water, and fill the egg with thin sirup 

 colored with an aniline dye. A test tube drawn out in a 

 flame to a fine tube is an excellent funnel for this purpose. 

 Hold a piece of small glass tube, about one meter long, 

 upright against the upper end of the egg and over the 

 hole, and fasten it firmly in position, and water tight, by 

 means of melted sealing wax. Keep the bottle filled with 

 water, and watch the progress of the experiment. In ab- 

 sorbing water from the bottle the artificial cell formed by 

 the egg and sirup acts practically in the same manner as 

 the root hairs in absorbing water from the soil. 



46. Make a cross section of a root of corn or bean and 

 treat with phloroglucin (see page 387). The elements which 

 are colored red are the water-conducting elements into 

 which the water passes from the root hairs. They are in 

 reality long tubes, formed by the fusion of elongated 



