CATALYSIS AND THE ENZYMES 



characteristic is missing which most manifestly 

 directs our attention to respiration as a process of 

 combustion. It is the development of free caloric 

 energy. But it is not difficult to show by means of 

 suitable contrivances that each plant produces an 

 abundant quantity of heat in respiration. We 

 only have to keep germinating seeds in a Dewar- 

 glass for several days to show that the temperature 

 in the glass rises to 40 degrees and more. Careful 

 isolation therefore is sufficient to demonstrate 

 this production of heat. Physiological investiga- 

 tion taught that in both animals and plants the 

 materials of combustion are essentially the same. 

 Most frequently large quantities of fat, sugar, or 

 carbohydrates disappear during the process of 

 respiration. The striking feature in such chemical 

 processes in life is that these substances are not 

 used to produce new cell-substances, but in the 

 first place to furnish free energy, which is used to 

 maintain the life-processes. 



The growth and the amount of respiration in a 

 fungus or in germinating seeds show what great 

 quantities of carbon dioxide are produced in a short 

 time, and how much sugar is consumed in respira- 

 tion. When we try to compare this vital decom- 

 position of sugar with the sugar-decomposing 

 processes which we apply in the laboratory, we 

 shall find it astonishing what effects are produced 

 in living cells without any high temperature, any 

 strong chemical reagent or electric current. A 

 M7 



