CHEMICAL PHENOMENA IN LIFE 



lump of sugar may be exposed to the air for years 

 without showing more alteration than that it turns 

 slightly yellow. Thus we come to the conclusion 

 that organisms must possess special means which 

 produce the rapid decomposition of respiration 

 material. 



The chemist Schoenbein, of Basel, was the first 

 to show that enzyme-like substances take part in 

 vital oxidation. He drew attention to the property 

 of many plant tissues of turning a colourless emul- 

 sion of resin of guaiacum in water blue. He then 

 showed that the effect on the guaiacum resin is 

 also found in the filtered watery extract of the 

 tissue, and that this oxidising effect cannot possibly 

 be obtained if the extract be boiled beforehand. 

 Later on numerous substances were found to be 

 such oxidising ferments. All plant and animal 

 cells contain such enzymes. But they act only on 

 aromatic substances, as phenols and resin acids ; 

 on sugar or on fat they do not show any effect. 



The explanation of this fact came from the 

 discovery that pea-seeds, which are brought to 

 germination without access of air, produce a large 

 quantity of alcohol besides carbon dioxide. This 

 process, which is found widely spread in plants 

 which are kept without oxygen from the air, 

 proved to be fully identical with the alcoholic 

 fermentation of yeast. Even the enzyme which 

 Buchner had found in yeast and had called zymase 

 was stated to be present in higher plants. We 

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