ANALYSIS or HEDGE HYSSOP. 367 



The matter insoluble in alcohol, that has been mentioned Mattei insolubl« 

 above, had no taste, and was redissolved entirely by water, ^"^^^'i^g^^'*^ *^^* 

 to which it gave a viscous consistence, as a gum would have 

 done. 



To satisfy myself whether it were really a gum, I digested 

 it in hot nitric acid, which soon took away its colour, and 

 dissolved it. The solution only remained of a light yellow. 



When thus treated by nitric acid, it yielded a white fioc- Treated with 

 culent substance, insoluble in water, which I took at first nitric acid. 

 for mucous acid; but farther experiments led me to con- 

 sider it as a mixture of this acid and oxalate of lime. 



To obtain this white powder separate, I decanted the White powdet 

 supernatant yellow liquid, and afterward washed the resi- ^^^^"^^ 

 , duum with small portions of cold water, till it was very 

 •white; when I separated it by the filter, and dried it. 



This powder had a slight acid taste; and, being diluted Its properties, 

 with a little water on litmus paper, it reddened it percepti- 

 bly. Placed on a burning coal, itswelled up, grew black, 

 and emitted a smoke that smelt exactly like that of sugar 

 treated in the same manner. In ammonia it appeared at 

 first to dissolve; but soon after a flocculent substance form- 

 ed in the liquid. 



Having filtered the ammoniacal solution, I added a few 

 drops of nitric acid, to saturate the alkali; and see whe- 

 ther the mucous acid, being little soluble, would not fall 

 down : but the mixture remained perfectly clear. To the 

 same solution I added lime-water, till the slight excess of 

 nitric acid it contained was saturated; but no precipitation 

 'took place. Lastly, I mixed a pretty large quantity of 

 alcohol with the ammoniacal solution, which produced in 

 it no change. 



From these experiments it appears, that the ammonia, 



with which I treated the white powder in question, dis- 



« solved no oxalic acid; since lime-water, added to it, did 



not render it turbid : and also, that it dissolved no mucous 



•acid, since I could not cause any to reappear. 



Yet it must have dissolved something; for the white Mucous acid, 

 'powder was reduced to a very small quantity ; and I am in- 

 clined to believe, both from the external appearance of the 

 substance, and from the smell of burnt sugar it emitted 



when 



