42 THE ORIGIN AND EVOLUTION OF LIFE 



forms carbonic acid, one of the few instances of biological 

 decomposition of water. This compound is so unstable that it 

 has never been obtained. Carbon dioxide is derived not only 

 through chlorophyllic agencies by means of free oxygen, but 

 also by the action of certain anaerobic bacteria and moulds 

 without the presence of free oxygen, as, for example, through 

 the catalytic action of zymase, the enzyme of yeast, which is 

 soluble in water, Loeb^ dwells upon the importance of the 

 bicarbonates as regulators in the development of the marine 

 organisms by keeping neutral the water and the solutions in 

 which marine animals live. Similarly the life of fresh-water 

 animals is also prolonged by the addition of bicarbonates. 



^ Loeb, Jacques, 1906, pp. 96, 97. 



