1 86 THE BEGINNINGS OF LIFE. 



that many of the processes which habitually take place 

 in living organisms are essentially similar to processes 

 of fermentation. It is, indeed, commonly recognized 

 that the salivary and various other alimentary secre- 

 tions when mixed with the elements of the food during 

 digestion, incite processes essentially fermentative 

 in nature. The transformation of starch into sugar, 

 which takes place during the germination of the seeds 

 of cereals and other plants, may be considered to belong 

 to the same category. Further, Liebig says * : — ^ Many 

 plants with woody stems are found to contain, in 

 autumn, a matter perfectly like the starch of potatoes, 

 or of the cereals, deposited in the substance of the 

 wood, which in the spring, when the plants re-awaken 

 to life, becomes converted into sugar. The ascending 

 juice of the maple is so rich in sugar, that in regions 

 where this tree occurs in such numbers as to form 

 forests^ its juice is employed in the manufacture of 

 sugar.' And, again_, he adds : — ^ The maturation, as it 

 is called, or sweetening of winter fruits^ when stored 

 up for their preservation in straw, is the result of a 

 true fermentation. Unripe apples and pears contain 

 a considerable amount of starch, which becomes con- 

 verted into sugar by the nitrogenous constituent of the 

 juice passing into a state of decomposition, and trans- 

 mitting its own mutations to the particles of starch in 

 contact with it.' 



There are, therefore, undoubtedly many striking 



^ 'Letters on Chemistry,' 1851, p, 201. 



