44 



EXPERIMENTAL PLANT PHYSIOLOGY. 



plant for the oxidation of another is termed intramolecular 

 respiration. This form of respiration is carried on to some 

 extent by all plants, but is characteristic of the germination of 

 oily seeds and of Yeast, Bacteria, etc. 



Respiration is essentially the same process in both plants 

 and animals, but while the former breathe and give off carbon 

 dioxide constantly from all parts of their bodies, the latter, 

 in the highly-developed forms, breathe rhythmically and for 

 the greater part by means of organs especially adapted for the 

 purpose. Yet there are instances among both plants and 

 animals where the respiratory processes are suspended or re- 

 duced for a period of varying length. 



35. Absorption of Oxygen and Excretion of Carbon Dioxide. 

 The amount of carbon dioxide given off in respiration is 

 FIG. 39. FIG. 40. 



Liberation of carbon dioxide by 

 respiration. (Mangin.) a, 

 baryta-water. 



approximately equal to the 

 oxygen taken up. The 

 proportion of the two sub- 

 stances varies with the tem- 

 perature and other condi- 

 tions, and in the different organs. De Saussure found that i 

 gram of seed of Hemp absorbed 19.7 cc. of oxygen and exhaled 



Cylinder containing germi- 

 nating Peas. (Sachs.) 



