297 



He remarked that, after having both last year and this demon- 

 strated that the Chinese sugar cane produces, when ri[)e, true 

 cane sugar with its perfect crystals, having all the replacements 

 and secondary forms belonging to cane sugar, and wholly incom- 

 patible with the forms of grape sugar, or glucose, and having 

 publicly made this demonstration before the Society, by aid of 

 excellent microscopes, he could not consider the nature of the 

 sugar an open or undecided question, about which members had 

 a right to entertain different opinions. It was an absolute 

 demonstrated fact, beyond question. He had shown that the 

 unripe plant produces grape sugar, which is readily crystal- 

 lizable by suitable operations, and the form of those ciystals is 

 that of grape or fruit sugar, wholly incompatible with that of the 

 cane sugar so abundantly found in the ripe plant. He stated 

 that the ripe sorghum juice gives from 12 to 18 per cent, of 

 saccharine matter, and, by the usual process of sugar-making in 

 a practical way, nine per cent, of good crystallized cane sugar. 



He had operated also on the Implice, which, when unripe, 

 gave also grape sugar, and, when ripe, good crystallized cane 

 sugar. The failui-es alluded to by Dr. Hayes, as having taken 

 place at the South, were from operations on the unripe Imphee in 

 South Carolina. 



Dr. A. A. Hayes read the following paper, on a chem- 

 ical change which takes place in the glucose of the 

 sorghum : — 



In a paper communicated to this Society some months since, I 

 alluded to the fact, that the glucose of the sorghum cultivated in 

 New England, like fluid fruit sugar, passes to the condition of 

 dry, or crystalline fruit sugar. The subsequent more careful 

 investigation of this change led to the observation, that the action 

 is continuous, proceeding indeed during many months, and 

 resulting finally in the production from pure glucose of sugar 

 having the higher grade of a variety of heet root, or cane sugar. 



In the account which follows, the experiments were made on 

 the glucose of that variety of sorghum which has dark purple 

 seed coverings, the variety generally cultivated in our northern 

 States. 



