NEW CONCEPTIONS IN SCIENCE 



it was that Croft Hill's bold announcement, three 

 or four years ago, of the discovery of " reversible 

 zymohydrolysis " was not starred in large type in 

 the public prints the next morning. But this 

 young Englishman had shown that a constructive 

 ferment exists; or, rather, that under given con- 

 ditions the destructive action of the ferment is re- 

 versible. 



When starch, or dextrine, is submitted to fer- 

 mentation by the malt enzyme, it is hydrolyzed 

 that is to say, split by taking up water, into one 

 of the simpler sugars, glycose. But if the resulting 

 product is not removed, the action soon comes to a 

 stand-still. Add more starch, it will begin again; 

 but add to the quantity of sugar, and the reverse 

 process is begun; the glycose is converted into 

 starch. The enzyme, then, is able to rebuild the 

 molecule it has pulled apart. 



Very recently a German chemist, Emmerling, has 

 found a yet more striking example. Under the 

 influence of one ferment, an extract of almonds 

 amygdaline may be broken up into sugar, hydro- 

 cyanic acid, and the essence of bitter almonds. 

 Another ferment, that of malt, again, will put 

 these products together to form the original com- 

 pound. Still other of these curious jacks-of -all- 

 trades seem able, in many cases simply by the ex- 

 traction Of water, to solder together the simpler 



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