CHAPTER I. 



ON SOME OF THE CONDITIONS AFFECTING THE 

 LIFE OF PLANTS. 



Section A. Respiration. Section B. Temperature — 

 Poisons — Electricity. 



Section A. Respiration. 



The presence of free oxygen is a necessary condition of 

 the life of all the higher plants. This fact will be more 

 conveniently demonstrated in the chapters dn growth and 

 grow-curvatures. The present section is intended as an 

 introduction to the study of the facts without special 

 reference to the importance of respiration. 



(1) Take a stoppered jar of about 500 c.c. capacity, 

 fill it to one-third of its height with horse-chestnut buds 

 (in spring) or with beans (in winter) which have been 

 soaked in water for 12 hours and have been afterwards 

 placed in damp cocoa-fibre for 12 hours. Place the jai' in 

 a warm, dark room, and after 12 hours cautiously open the 

 jar and lower a lighted taper which will be extinguished 

 as it enters the CO2 produced. 



D. A. 1 



