348 THE BIOLOGY OF THE PLANT 



dry and of germinating seeds. Can you trace 

 any connection between this experiment and the 

 transfer of food-material from the storage leaves 

 or cotyledons into the growing parts of the seed- 

 ling plant ? 



Make sections of a cotyledon of a bean plant 

 which has developed two or three pairs of leaves. 

 Do you find as much starch present as before 

 germination ? Explain. 



B. — Stems 



Material. — Provide as specimens of the woody plants 

 stems about two feet long of the horse-chestnut, elm, 

 maple, willow, cherry, and pine. These should be 

 taken during the winter or before the leaves expand in 

 the spring. If to be examined during the early summer 

 they may be preserved by being placed for a day in fif- 

 ty per cent., and then kept permanently in eighty per 

 cent, alcohol. To compare with these have fresh or al- 

 cohohc material bearing the expanded leaves and the 

 flowers. It is possible to use dried specimens, but only 

 as a last resort. For herbaceous stems use the Bego- 

 nia or Geranium, Tradescantia ("Wandering Jew), and 

 strawberry, all of which may be had in the garden at 

 certain seasons or at the greenhouse at any time of 

 year. Have also a metric scale, dividers or calipers, 

 forceps, hand-lens, razor, compound microscope, Schulze's 

 solution, iodine, acetic acid carmine, Schulze's macerat- 

 ing mixture, acetic acid, hydrochloric acid, phloroglu- 

 cin, sponge, bell-jar, small camel's-hair brush, India ink, 

 and scalpel. 



Method of Examination. — First study the arrange- 



