On the Rhus Glabrum and Sambucus Canadensis. 43 



To determine the nature of this acid, I made the following ex- 

 amination : 



1. A strong infusion of the ripe berries was made by pour- 

 ing warm distilled water on them, and using a fresh portion of 

 berries, until a very acid liquor was obtained. 



2. This liquor was filtered, and a solution of potassa added 

 to it, till it became neutral. To ascertain whether the acid 

 was the tartaric, another portion of the acid liquor was added ; 

 but no crystals of supertartrate of potassa were formed. 



3. Another portion of the acid was saturated with carbonate 

 of lime; this was filtered and concentrated, a salt of lime was 

 formed, which was insoluble in cold water, but dissolved rea- 

 dily in water boiling hot. To the solution in boiling water, 

 alcohol was added, which gave a beautiful coagulated white 

 precipitate. This, when dried, was readily dissolved in hot 

 water. 



4. The acid solution was then treated with subnitrate of 

 mercury ; it formed a dirty white precipitate. 



5. With acetate of lead, it produced the same result. 



6. With sulphate of iron, a small portion of gallic acid was 

 detected. 



From these experiments I conclude that the acid of the su- 

 mach is the Malic, and that it is nearly pure, being only con- 

 taminated with a small portion of gallic acid, which probably 

 proceeds from the pulp of the berries. 



On carefully inspecting the sumach berries, they are seen to 

 be clothed with a down or pubescence, and the acid principally 

 resides in this substance ; for after it is washed off by warm 

 water, the berries are entirely free from any acid taste. 



I shall conclude this part of the paper with a process for 

 preparing, with very little trouble, a pure malic acid from these 

 berries, which may be used for some of the purposes of the 

 citric acid. 



Process. Rub the berries in boiling rain or distilled wa 

 ter ; filter the liquor, and evaporate it in a ivell tinned vessel, 



