MALIC ACID. 951 



tartaric acid loses water when heated, and gives rise to two 

 new and peculiar acids, corresponding in composition with 

 tartralic and tartrelic acids. At a still higher temperature, 

 it gives rise to a body which is identical in properties with 

 anhydrous tartaric acid. It gives also by dry distillation the 

 same two pyrogen acids as tartaric acid. 



SECTION VI. 

 MALIC ACID. 



Formula of the hydrated acid; 2HO-fC 8 H 4 O 3 . Malic acid 

 is bibasic (Hagen). 



This is the acid of apples, from which it derives its name, 

 but is of frequent occurrence in other acidulous fruits and vege- 

 table juices, where it is accompanied by citric and tartaric acids. 

 It is generally prepared from the berries of the mountain ash 

 (Sorbus acuparia). The fruit is collected in August, while 

 scarcely red and before it is ripe. It is bruised in an iron 

 mortar, the juice expressed, filtered through linen, and treated 

 in a bason of copper with a thin milk of lime till the mixture 

 commences to change colour. An excess of lime occasions a 

 deep green coloration, but the liquid ought to have a slight 

 acid reaction, and to retain a reddish brown colour. When 

 now made to boil, a large quantity of a neutral malate of lime 

 precipitates, crystalline and granular, which may be taken out 

 as it collects, by means of a colander. After this is deposited, 

 a new portion of milk of lime may be added, with the same 

 precautions, and a fresh portion of malate of lime is obtained. 

 This salt is washed cold, and introduced while still humid into 

 a boiling mixture of 1 part of nitric acid and 10 parts of water, 

 so as to dissolve it. A concentrated solution deposits on cool- 

 ing a large crop of colourless and regular crystals, of the acid 

 malate of lime. The addition of acetate of lead to the purified 

 acid malate of lime, throws down a curdy white precipitate, 

 which contains lime, but on allowing it to digest at a moderate 

 heat in an excess of acetate of lead, the lime is abandoned, and 

 crystals form in four-sided prismatic needles, grouped about & 

 common centre, and possessing a silky lustre, which are neu- 

 tral malate of lead, containing 6 atoms of water of crystallization. 



