310 ON DIFFERENT SPECIES OF SUGAR. 



the sugar we derive from plants, resemble it likewise in two 

 points worthy of remark. The first consists in the two de- 

 grees of consistency ; the one solid, the other soft, which in 

 like manner divide all the vegetable sugars: the second in 

 the flavour, which is commonly more sweet or saccharine 

 in the fluid honeys and sugars, than in those which are 

 crystallizable. 

 The solid por '^^^ ^^^'^ sugar of honey is not similar to that of the 

 tions not com- cane, either in flavour or crystallization : but in both these 

 men sugar. qualities it comes so near the sugar of the grape, that I 

 begin to doubt whether there be much difference between 

 Their separa- them. Unquestionably it would be an important advan- 

 tion difficult, tage to society, to be able to separate the two species of 

 sugar, thnt compose most kinds of honey, in order that 

 each might be employed exclusively for those purposes, to 

 which it is best adapted : and though at present T see no 

 hope of succeeding in this but by the mean of spirits of wine, 



which would be far from economical, I cannot avoid think- 

 but the grape 

 may render us ing, that the result would be one step toward the emanci- 



'!f'^h'*^w^'^* pation, for which a great part of Europe is anxious, if the 



Jndies. sugar of grapes did not ofl"er itself, to hasten a period so do-? 



sirable. 



Manna. It has long been supposed, that the softness of manna, 



Itssoftness not and the readiness with which it grows moist, were owing to 



owmg to ex- ^^ extractive matter ; and that this matter, covering the 



tractive. ,...,.,. , , . , i « 



qualities in which it resembles sugar, must be the cause or 



its laxative virtue. If however we examine its solution with 



muriate of tin, we find but very little precipitate : and 



alcohol dissolves manna completely, contrary to the opinion 



of Lemeri. This solution, left exposed to the air, dries into a 



porous mass composed of very slender crystalline filaments 



and granular particles, which by its lightness resembles a 



fine white agaric, 



Tt • d' f t Manna thus refined does not approach the sugar of the 



species of su- cane: its moistness and faint taste are still the sarne^ It is 



f^"^* not in its nature therefore, to be any thing but what it ha? 



always appeared to us, that is to say, a species of sugar, the 



characteristics of which are softness, an unpleasant taste, 



and the medicinal properties for which it is used. To ascer- 



^fiin whether manna likewise have its two species, and be in 



this 



