SUCCINIC ACID LACTIC ACID. 9 



still, and pouring over the mixture sulphuric acid, diluted with 

 water. An effervescence takes place, and formic acid may be 

 distilled over. Wdhler and Liebig have shown that sugar, starch, 

 &c. may be substituted for tartaric acid. But, as the preparation 

 of this acid has been minutely described in the Chemistry of 

 Vegetable Bodies, (p. 17), the reader is referred to that work. 



The characteristic property of formic acid is this : When 

 formic acid or formate of soda is put into a solution of any salt 

 of gold, platinum, or silver, an effervescence takes place, and 

 the gold, platinum, or silver is deposited in the metallic state. It 

 effervesces also, and reduces to the metallic state oxide of silver 

 and oxide of mercury. 



This acid has been shown to consist of C 2 HO 3 = 4.625. It 

 differs from oxalic acid by containing an atom of hydrogen, while 

 oxalic acid is C 2 O 3 = 4.5. 



SECTION III. OF SUCCINIC ACID. 



This acid has been known for nearly a century. The mode of ob- 

 taining it, together with its properties and constitution, has been 

 given in the Chemistry of Inorganic Bodies, (Vol. ii. p. 89.) A 

 curious discovery made by M. Bromeis during the course of the 

 winter 1839-40, makes it necessary to introduce it here. He 

 found that when nitric acid is made to act upon stearic acid, 

 one of the products obtained is succinic acid.* When the nitric 

 acid solution formed is evaporated to one-half, it concretes in 

 twenty-four hours to nearly a solid mass, which, when put into a 

 glass funnel, and washed with cold water, is freed from the mother 

 ley. When these washings are concentrated, they yield a white 

 firm crystalline salt ; which Bromeis found to be succinic acid 

 composed of C 4 H 2 O 3 + HO, and agreeing in all its properties 

 with succinic acid from amber. 



v 



SECTION IV. OF LACTIC ACID. 



This acid is formed when milk becomes sour. It was first ex- 

 amined by Scheele, who pointed out its most remarkable proper- 

 ties, and noticed its analogy to acetic acid.f He called it milk 

 acid, which was afterwards converted into lactic acid, as more 



* Annalen der Pharmacie, xxxv. 90. 



t Kong. Vet. Acad. Handl. 1780, p. 116, or Scheele's Essays, p. 273. 



