ON THE PRUNE 



into a form of sugar before it is fermented in the 

 manufacture of alcohol. How, then, does the sugar 

 in the prune prevent the fermentation of the fruit 

 and insure its preservation? 



The answer is that sugar ferments only under 

 influence of certain living micro-organisms, and 

 that these micro-organisms cannot work in a too 

 concentrated solution of sugar. There are myriads 

 of the microbes spread broadcast everywhere on 

 the wind, and of course they find lodgment on the 

 skin of the prune as on every other exposed 

 surface. 



But the alkali bath to which the prune is 

 subjected, destroys these germs at the same time 

 that it cracks the skin of the fruit. 



Other germs would find lodgment, however, 

 and set up fermentation, were it not that the 

 cracked skin permits a very rapid evaporation of 

 the water content of the fruit. This quickly brings 

 the sugar content to a degree of concentration that 

 makes it a powerful antiseptic that is to say a 

 germicide that destroys any micro-organisms that 

 enter it. 



But unless the prune has at least 15 per cent of 

 sugar in its pulp, it will take too long to desiccate 

 it sufficiently to give the sugar the right degree of 

 concentration. And unless the conditions are very 

 exceptional, even when the plum has a sugar con- 



[93] 



