An Investigation of the Properties of Lactic Acid. 245 



©r like malate of lime. Bv boiling with more lime, and by 

 the precipitation of the superfluous base upon exposure to 

 the air, it becomes pure and soluble in alcohol. _ 



Lactate of ma^nena, evaporated to the consistence oi 

 a thin syrup, and left in a warm place, shoots mto small 

 granular crvstals. When hastily evaporated to dryness, it 

 aftords a gummy mass. With regard to alcohol, its pro- 

 perties resemble those of the two precedmg salts. _ ^ 



Ammoniaco-magnesian lactate is obtained by mixing the 

 preceding salt with caustic ammonia, as long as any preci- 

 phafon continues. By spontaneous evaporation this salt 

 shoots into needle-shaped prisms, which are little coloured, 

 and do not change in the air. 1 have once seen these 

 crystals form in the alcoholic extract of nnlk boiled to 

 dryness : but this is by no means a common occurrence. 



The lactate of silver is procured by dissolving the car- 

 bonate in the lactic acid. The solution is ot a light yellow 

 somewhat inclining to green, and has an unpleasant taste 

 of verdigris. When evaporated in a flat vessel, it dries 

 into a very transparent greenish yellow varniSh, which has 

 externally an unusual splendour like that of a looking-glass. 

 If the evaporation is conducted in a deeper vessel, and with 

 a stronger heat, a part of the salt is decomposed, and re- 

 mains brown from the reduction of the silver. It this salt 

 is dissolved in water, no inconsiderable portion of the silver 

 is reduced and deposited, even when the salt has been 

 transparent; and the concentrated solution has a fine 

 greenish yellow colour, which by dilution becomes yellovv. 

 If we dissolve the oxide of silver in an impure acid, the salt 

 becomes brown, and more silver is revived during the eva- 

 poration. • 1 • 1 u 



The lactate of the protoxide of mercury is obtained when 

 the lactic acid is saturated with black oxidated mercury. 

 It has a lio-ht yellow colour, which disappears by means of 

 repeated solution and evaporation. The salt exhibits acid 

 properties, deliquesces in the air, and is partially dissolved 

 in alcohol, but is at the same time decomposed, and de- 

 posits carbonate of mercurv, while the mixture acquires a 

 slight smell of ether. The lactic acid dissolves also the 

 red oxide of mercurv, and gives with it a red gummy deli- 

 quescent salt. If it is left exposed to a warm and moist 

 atmosphere, it deposits, after the expiration ol some weeks, 

 a light semi-crystalline powder, which 1 have not examined, 

 but^'which probably must be acetate of mercury. 

 Ti\& Lactate of lead maybe obtained m several different 

 Q 3 degrees 



