CONSTITUENTS OF PLANTS, ETC. 335 



sugar. An infusion of brewer's malt can be used in this 

 process in place of the dilute sulphuric acid. 



The process by which wood or cellulose is converted into 

 sugar is a little different. The wood must be in the form 

 of saw-dust. This is moistened with a little over its own 

 weight of sulphuric acid, and is left to stand for twelve 

 hours. The mass becomes very nearly dry in that time, 

 but on being pounded in a mortar it becomes liquid. "Wa- 

 ter is added to it, and boiling completes the transformation, 

 giving you a sirup which is to be treated in the same way 

 as that obtained from starch. Some kinds of wood yield 

 more sugar than others. Poplar wood is found to be the 

 best, every five pounds of the wood yielding four of sugar. 

 As the fibre of cotton and of linen is really cellulose, sugar 

 can be made by the above process from cotton and linen 

 rags. 



The explanation of this reaction has been anticipated in 

 455, in explaining the formation of dextrin. We need 

 hardly say that no way has yet been discovered of convert- 

 ing cellulose or starch into cane-sugar. If such a discovery 

 could be made it would be a vast mine of wealth to the 

 discoverer.- 



462. Cheating in Sugar. Cane-sugar is often adulterated 

 in England and on the continent of Europe with this grape- 

 sugar made from starch and wood. Stockhardt states that 

 the white sugar sold in Germany " is frequently found to be 

 composed partly or entirely of starch-sugar." In England 

 the manufacture of it has been prohibited by law. The 

 profit on such adulteration must be very great, for the ma- 

 terials used are all cheap, especially if an infusion of malt 

 be used instead of sulphuric acid in effecting the conver- 

 sion. Grape-sugar is used extensively by brewers, being 

 cheap and easily undergoing fermentation. 



463. Starch and Wood changed into Sugar in Plants. We 



