STRUCTURE 33 
hole into the upper end of it about 1.5 cm. in diameter 
and 5 to 8 cm. deep; make sure that the auger does not 
break thru the surface. Fill the cavity with molasses or 
a strong sugar solution and close it with a cork con- 
taining a hole about 2 mm. in diameter. Set the carrot 
into a two liter jar full of water; select a glass tube to 
fit the hole in the cork and 2 meters or more long, thrust 
one end of the tube into the hole in the cork and support 
the other so that it will stand vertical. Short glass tubes 
may be spliced with rubber tubing if there are no long 
ones at hand. Record the elevation of the solution in the 
tube and look for changes during the next 24 hours. 
What causes the changes? What phenomenon in the 
physiology of plants does this experiment illustrate? 
| Exp. 22: Cut 5 to 10 cm. from the lower end of a 
parsnip or horse-radish and.a large sweet-clover root 
bearing stems and leaves, and place them in a weak solu- 
tion of eosin. After 24 hours cut the roots longitudinally 
in half and also cut cross sections with a scalpel. How 
far did the solution rise? Thru which tissues did it pass? 
What caused it to rise? The results of exp. 21 should 
help you to answer the last question. 
Root Structure. 
The structure of roots is very much like that of 
stems. It will be only briefly studied. With a scalpel 
make cross sections of a young cherry, maple, or beech 
root about I cm. in diameter, and also of the clover root 
used in exp. 22. Note that-the root, like the stem, is 
composed of three kinds of tissue, bark, wood and pith. 
There is but very little pith. Make an outline drawing 
