CHAPTER VI 
THE PATH OF LIQUIDS IN THE PLANT 
69. The Problem Stated. We have seen that plants 
are continually losing water by transpiration, chiefly from 
the leaves, and making good the loss by absorption through 
the roots. The question now arises as to how the water 
passes through the stem to the leaves. Does it pass 
through the entire tissue of the stem, or is it confined to 
definite regions or channels? 
60. Demonstration of Channels. It will be easy to 
solve our problem experimentally by placing various 
stems or branches in liquid containing some coloring 
substance which will stain the tissues through which it 
passes. Common red ink may be used for this. Into 
water, colored with red ink, may be placed young seedling 
corn plants, stalks of celery, seedlings of castor-oil plants, 
leaves of plantain and lily, parsnips with a portion of 
the small end cut away, or any other available material. 
After the stems have been allowed to stand in the ink 
solution over night, they should be thoroughly rinsed, to 
remove the stain from the surface, and then examined 
by cutting off a small portion of the submerged buds. It 
will be clearly seen that the red coloring matter is not 
deposited throughout the tissue, but is confined to 
clearly marked channels the fibre-vascular bundles. These 
bundles will be found to be distributed differently ac- 
cording to the kind of plant or its age, or both. Two 
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