112 THE VEGETATIVE FUNCTIONS OF PLANTS 



TABLE III. COMPARISON OF PLANT AND ANIMAL RESPIRATION 



Plant respiration Animal respiration 



1. Oxidations occur within the tissue i. Ditto 



2. Oxygen taken in 2. Ditto 



3. Carbon dioxide given off 3. Ditto 



4. Heat evolved 4. Ditto 



5. Water-vapor formed 5. Ditto 



6. Dry weight decreased 6. Ditto 



7. Potential energy becomes kinetic 7. Ditto 



8. Occurs in every living cell 8. Ditto 



9. Occurs without ceasing, day and night 9. Ditto 



10. Accomplished by respiratory enzymes 10. Ditto 



114. Respiration and Fermentation. Perhaps one of 

 the most surprising and interesting of all the results of the 

 study of respiration is the revelation of the fact that 

 the real process of respiration (the oxidation of living tis- 

 sues, as distinguished from the exchange of gases by 

 breathing, or otherwise) is accomplished by enzymes 

 known as oxidases, and is therefore, in reality, a form of 

 fermentation. In fact, the more deeply we study all the 

 fundamental processes of living things, the more it 

 seems to become evident that every chemical process in 

 organisms, in fact, that life itself is absolutely dependent 

 upon fermentations. We are brought face to face with the 

 almost startling fact that such commonplace phenomena as 

 the ripening of fruit, the raising of dough, and the decay 

 of plant tissues, are conditioned by the same class of sub- 

 stances (enzymes), and by the same kind of processes that 

 underlie the digestion of food, the respiration of tissues, 

 and the thinking of human minds. And, moreover, we 

 seem to be led to the odd conclusion that living organisms 

 do not respire because they take in oxygen, but that they 

 take in oxygen because they have respired. 



