236 Intelligence and Miscellaneous Articles. 



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yielded the most. Water at 65° dissolved 10*91 per cent, of sugar of 

 milk, and at 2 1 2°, 9670 per cent. \ 100 parts of it heated with 600 parts 

 of nitric acid gave as a maximum product 2862 of mucic acid, mixed 

 with oxalic acid ; gum Senegal, which consists of arabin and water, 

 gave only 16*70 per cent, of mucic acid mixed with oxalic j but then 

 sugar of milk contains less than one per cent, of water, while gum 

 Senegal contains 16*1 per cent, and 2*78 per cent, more of ashes. 



Mucic acid, obtained either from sugar of milk or gums, when dis- 

 solved in boiling water, crystallizes on cooling in small scales, which 

 present on their edges small crystals, which appeared to be prisms 

 with a rectangular base. 



SUPPOSED ARTIFICIAL MALIC ACID. 



M. Guerin observes that Scheele obtained a peculiar acid, which 

 he called Malic acid, by the action of nitric acid upon mucilage. 

 Fourcroy and Vauquelin repeated these experiments, and described 

 a new uncrystallizable acid, which they considered as identical with 

 the malic acid of fruits, this acid not having then been obtained in a 

 crystalline state. 



In order to prepare this artificial malic acid, M. Guerin employed 

 the following process : one part of gum arabic was treated with two 

 parts of nitric acid, diluted with half their weight of water j the mix- 

 ture was heated moderately, until all the gum was dissolved, and the 

 solution was then slowly boiled for two hours. After dilution with 

 water it was neutralized with ammonia j muriate of lime was then 

 added to precipitate the oxalic acid formed, and the whole was thrown 

 on a filter j the filtered liquor was yellowish red, and solution of ni- 

 trate of lead was added to it ; a yellowish precipitate was obtained, 

 which, after being well washed, was decomposed by a current of sul- 

 phuretted hydrogen gas, and the acid liquor was evaporated with a 

 gentle heat j this was again saturated with ammonia, and decom- 

 posed by nitrate of lead j and the precipitate decomposed by sulphu- 

 retted hydrogen, gave an acid liquor, which, though evaporated to the 

 consistence of a syrup, gave no crystals. 



The properties of this acid are, that it is slightly yellow, reddens 

 litmus, its taste resembles that of malic acid, is inodorous, and more 

 dense than water. It is very soluble, both in water and in alcohol j 

 it causes precipitation in lime, barytes, and strontia water, which is 

 redissolved by excess of acid. The salts of lead give a bulky preci- 

 pitate with it, which is insoluble in cold water, and in excess of the 

 acid j boiling water dissolves a small portion, which crystallizes as 

 the solution cools. When this acid is neutralized by ammonia, and 

 heated, an acid salt is formed, which crystallizes in colourless prisms 

 with a rectangular base. Its taste is slightly acid ; cold water dis- 

 solves it sparingly, but boiling water readily. It is insoluble in al- 

 cohol. This acid may be obtained by treating one part of sugar or 

 of starch with half a part of nitric acid, in the same manner as al- 

 ready described with gum. M. Guerin concludes that this acid is not 

 the malic, as has generally been supposed, but that it is a new acid, 

 perfectly distinct from all others. — Ann. de Chinu et de Phys. torn. xlix. 

 p. 274. 



