22 CHEMISTRY AND PHYSICS IN RELATION 



DECOMPOSITION OF AMYGDALIN AND ASPARAGIN BY PUTREFYING 



SUBSTANCES, 



In contact with the nitrogenous constitutent of germinating barley (diastase) 

 asparagin is resolved into succinic acid and ammonia ; amygdalin resolves itself 

 with the nitrogenous constituent of sweet almonds (emulsine) into prussic acid, oil 

 of bitter almonds and sugar ; salicin into saligenin and sugar. 



THE CONVERSION OF STARCH INTO SUGAR. 



Potatoes and the flour of the cereal grasses contain no sugar. The mere contact 

 with water is sufficient, in consequence of the change that is thence effected in the 

 sulphurous and nitrogenous constitutents, to bring about a conversion of the starch 

 into sugar. 



THE SAME EFFECT PRODUCED BY ANIMAL MEMBRANE. 



Animal membrane, when moistened with water, causes sugar of milk and grape 

 sugar to pass into lactic acid ; a similar property is possessed by the gluten of the 

 cereal grasses, by animal casein, and by diastase. 



FERMENTATION AND ITS PROPERTIES. 



The property of an organic body to pass into the same state of putrefying 

 decomposition as the body with which it is brought in contact, is termed the 

 process of fermentation. 



DIFFERENT DEGREES OF PUTREFACTION, AND THEIR INFLUENCE 

 UPON FERMENTATION. 



If it be true that the change of form and property in the fermenting body 

 be dependent upon those which are effected in the putrefying body, or in 

 the agent of fermentation : if the new order of deposition of the atoms of the 

 one body, be influenced by the direction in which the parts of the other arrange 

 themselves ; if finally, the fermenting body behave as if it were a part or 

 constituent of the agent of fermentation, it is clear that the mode of separation in 

 the one must change with that of the other body ; the fermenting body must yield 

 other products if the disunion, or the chemical condition of motion change the 

 agent of fermentation. Innumerable experiments testify to the correctness of 

 these conclusions. 



MILK OF ALMONDS AND SUGAR. 



When the milk of almonds, which in its fresh state exercises no influence upon 

 sugar, is left for a short period of time, it ceases to act upon amygdalin : and if in 

 this condition sugar be added, the latter begins to ferment, and separates into 

 alcohol and carbonic acid. If the almond milk be left still longer, it converts the 

 sugar into lactic acid. A similar property is possessed by diastase, which, when 

 fresh, converts starch into sugar ; but after a period of eight days, it loses this 

 action, and gives to fermentation. 



