WORK OF THE STEM 79 



through the root-hairs of the growing plant it differs but 

 little from ordinary spring water or well water. The 

 liquid which flows from the cut stem of a " bleeding " 

 grapevine, which has been pruned just before the buds 

 have begun to burst in the spring, is mainly water with 

 dissolved organic acids, proteids, and sugar. The sap which 

 is obtained from maple trees in late winter or early spring, 

 and is boiled down for syrup or sugar, is still licher in 

 nutritious material than the water of the grapevine, while 

 the elaborated sap which is sent so abundantly into the 

 ear of corn at its period of filling out, or into the grow- 

 ing pods of beans and peas, or into the rapidly forming 

 acorn or the chestnut, contains great stores of food suited 

 to sustain plant or animal life. 



EXPERIMENT XI 



Rise of Water in Stems. — Cut some short branches from an apple 

 tree or a cherry tree and stand the lower end of each in red ink ; 

 try the same experiment with twigs of oak, ash, or other porous 

 wood, and after some hours ^ examine with a magnifying glass and 

 with the microscope, using the 2-inch objective, successive cross- 

 sections of one or more twigs of each kind. Note exactly the por- 

 tions through which the ink has traveled. Pull off the leaves from 

 one of the stems after standing in the eosin solution, and notice 

 the spots on the leaf-scar through which the eosin has traveled. 

 These spots show the positions of the leaf-traces, or fibro-vascular 

 bundles, connecting the stem and the leaf. Repeat with several 

 potatoes cut crosswise through the middle. Try also some mono- 

 cotyledonous stems, such as those of the lily or asparagus. For the 

 sake of comparison between roots and stems, treat any convenient 

 root, such as a parsnip, in the same way. 



1 If the twigs are leafy and the room is warm, only from 5 to 30 minutes 

 may be necessary. 



