MALIC, CITRIC, AND RACEHIC ACID. 249 



lime remained insoluble, but malate of lime soluble. 

 The insoluble lime salts were dissolved with muriatic 

 acid, and ammonia was then added to them. This gave 

 rise to a precipitate of tartrate of lime, and if racemic 

 acid had been present racemate of lime would also have 

 been deposited. Citrate of lime might still be pre- 

 sent in the filtered liquid, but as no precipitate could 

 be obtained by filtering and evaporating the ammonia, 

 we infer that citric acid is not contained in wine. The 

 liquid which flowed from the milk of lime was accurately 

 saturated with acetic acid. It gave a precipitate with 

 alcohol, which is a sign of the presence of malate of 

 lime. Acetate of lead gave rise to a precipitate which 

 is soluble in excess of acetate of lead, or when warmed, 

 but separates again when boiled. A green liquid, 

 but no precipitate, is obtained from it, by acetate of 

 copper, whilst nitrate of silver and sub-nitrate of 

 mercury gave a white precipitate ; these reactions all 

 indicated the presence of malic acid. 



Since, however, the slight solubility of the lead 

 salt prevented us from obtaining the malic acid, -when 

 the method described above was used, we adopted the 

 following plan : 



Wine was digested with chalk upon a water bath 

 till the acid reaction completely disappeared. The 

 watery liquid was filtered and precipitated by means 

 of alcohol. 



The precipitate was dissolved again in water and 

 re-precipitated by means of alcohol, and this process 



