EXPERIMENTS 45 
perature of the room. Place the jar containing the 
branches in direct sunlight. Note that bubbles of gas 
pass from the cut ends of the branches. After the jar 
has been in sunlight 10 minutes ascertain the number of 
bubbles given off per minute. Put the jar into strong 
diffused sunlight and 10 minutes later ascertain the rate 
of the bubbles per minute. Then put the jar into total 
darkness and 10 to 20 minutes later again ascertain the 
‘rate. Results; conclusions? | 
What is the gas given off largely composed of? 
Is there any gas given off by these green plants in dark- 
ness? If so, what becomes of it? 
Respiration. 
Exp. 3a, Class: Early in the forenoon put a green 
plant in place of the peas in the apparatus used in exp. 
9. Set the apparatus into strong diffused sunlight and 
keep it running very slowly all day and the following 
night. Results, (1) in the light, (2) in darkness? Con- 
clusions? 
Transpiration. 
Exp. 33, Groups of Two: Pass the cut end of a twig 
bearing several leaves thru a small hole in a cork into 
some water in a small bottle. See that the cork fits the 
bottle so as to make it practically air tight. Put the bot- 
tle with the twig, whose leaves must be dry, into a dry 
fruit jar, close the jar tight, and set it in a well lighted 
place, but not in direct sunlight. Make observations late 
in the afternoon of the following day. Do you find any 
moisture condensed on the inner surface of the jar? 
Conclusions? 
