STEMS 97 



chloric acid (see Exercise 40). Pour the gas into the fruit jar, 

 but do not pour over any of the liquid (see Exercise 15). From 

 time to time close the mouth of the fruit jar with your hand, 

 or with the cover belonging to the jar, and shake the jar vigor- 

 ously, so as to make the gas dissolve in the water. 



Fill a quart fruit jar (see Fig. 235, 310, text) loosely with pars- 

 ley or spinach; then add the carbon dioxide water to overflowing. 

 Invert the jar (do not let any air bubbles enter) in a pan of the 

 carbon dioxide water. Let the bottle stand in bright sunlight 

 for two days, if possible. Do gas "bubbles collect over the water? 



Transfer the gas, under water (see Fig. 78, 102, of text), 

 to a test tube filled with water and inverted in the water. If 

 the gas does not fill the test tube, close the mouth of the test 

 tube, under water, with your thumb; then remove the test 

 tube and invert it. Test the gas with a glowing splinter. 

 What is the gas? What change did the leaves bring about? 



EXERCISE 91 

 STEMS 



Apparatus and Materials. Pocket knife, pocket magnifier; young 

 twig and older stem of lilac, box elder, oak, poplar, cherry, elm; corn- 

 stalk, handle of palm leaf fan or a palm leaf; a potato, also one that 

 has sprouted in the dark; rhubarb stalk; red ink. 



a. Read 312, 313, 314, and 315, text. Examine the young 

 twig and an older stem of a lilac. Describe the color and appear- 

 ance of the bark. Look for marks of any kind. Where are the 

 nodes? Can you find the scars of leaves of other years? How 

 are they arranged? How are the buds related to the leaf scars? 

 Do the buds go singly, or in pairs? How is one set of buds 

 arranged with respect to the next set? Is it directly above it? 



Cut across a bud, and describe what you see. Has your 

 twig a growing tip? Describe it. 



