299 



this agent enables us to learn at any moment the production of 

 sugar in a sample ; the sugar when formed being nearly insolu- 

 ble in cold alcohol. Thus, when a certain number of crystals 

 have formed, if we withdraw by solution in alcohol the unchanged 

 glucose, and after dissipating the alcohol, allow it to repose, 

 crystallization recommences in the portion removed, and repe- 

 tition^ of this experiment may be made, until after about ten 

 months, small portions only of unaltered glucose remain. 



Although the evidence of the conversion of the glucose, step 

 by step, into sugar, aiForded by the action of alcohol, is impor- 

 tant, the observations here recorded are based upon experiments 

 made in a similar manner, with the alkaline solution of tartrate 

 of copper, and acidulated alcohol saturated with cane sugar ; they 

 leave no doubt that the normal saccharine juice of the plant be- 

 comes, per se, converted into sugar, forming regular crystals of 

 large size. These crystals, by solution in water, are easily puri- 

 fied, losing their porous structure and becoming solid, transpar- 

 ent, and colorless modifications of the rhombic prism from an 

 aqueous solution. They are always apparently more volumi- 

 nous than the crystals of cane sugar, formed under like circum- 

 stances, but they have all the brilliancy of cane sugar. In 

 chemical characters, the most pure crystals yet obtained show a 

 diversity when compared with cane or palm sugar. They are 

 less soluble in water ; in sulphuric acid they do not exhibit the 

 same depth of coloration that cane sugar does. With the copper 

 test, a partial I'eduction takes place, under the same conditions, 

 where cane sugar does not produce change on this agent. 



The conclusion reached is, that this sugar, wholly unlike any 

 variety of glucose or fruit sugar, belongs to a higher class, and 

 probably will rank with beet sugar, in most of its characters. 



The present is the first instance, within my knowledge, of the 

 conversion of any variety of glucose into a sugar of high grade, 

 after its extraction artificially. 



Dr. Jackson remarked that the statements made by Dr. Hayes 

 in his paper were so extraordinary, and so opposed to the expe- 

 rience of both scientific and practical men, that those results 

 should be verified by others before they could be believed. If 

 Dr. Hayes had discovered that the juice of the sorghum, after it 



