Products of the Distillation of Meconic Acid. 133 



rakomenic acid is but slightly soluble, while pyrorneconic acid 

 very readily dissolves. 



The parakomenic acid when first sublimed is usually of a 

 deep yellow colour, but this is removed by dissolving it in 

 boiling water, and digesting it with animal charcoal. When the 

 filtered solution cools, the parakomenic acid is deposited in 

 hard crystalline grains, with merely a faint tinge of yellow ; 

 their powder is quite white. The crystals of parakomenic 

 acid, if not quickly dried, become of a pale red colour, and 

 their solutions, though reddish while cold, become nearly co- 

 lourless when heated. In appearance, degree of solubility in 

 water and alcohol, and in their strongly acid taste and reac- 

 tion, they closely resemble komenic acid, from which they 

 differ however in some particulars, as I shall presently notice. 

 When dried at 212° F. and analysed with chromateof lead, — 



I. 0*3319 gramme of substance gave 0*5603 grm. of carbonic 

 acid and 0-0805 of water. 



II. 0*2788 gramme of substance gave 0*470 of carbonic acid 

 and 0*071 of water. 



III. 0-3873 gramme of substance gave 0*653 of carbonic 

 acid and 0*09 1 2 of water. 



100*00 10000 100-00 100*00 



It is evident from the results of these analyses, that the com- 

 position per cent, and formula, both of komenic and parako- 

 menic acids, are the same. Though this is the case, and 

 though they closely resemble each other in most of their pro- 

 perties, the two acids may be easily distinguished by the fol- 

 lowing reactions : — I. Parakomenic acid produces no preci- 

 pitate in a solution of acetate of copper, while komenic acid 

 causes a copious yellowish-green precipitate. II. When 

 added to neutral acetate of lead, parakomenic acid throws 

 down a small quantity of a white granular precipitate, which 

 instantly disappears if the liquor is stirred, being apparently 

 dissolved by the free acetic acid present, for it reappears and 

 remains permanently on the addition of a few drops of am- 

 monia. Komenic acid, on the contrary, causes in acetate of 

 lead a bulky, slightly yellowish precipitate, which does not 

 dissolve even when treated with a great excess of acetic acid. 

 Neither komenic nor parakomenic acids precipitate salts of 

 lime, barytes, or strontian. They produce no change in solu- 

 tions of corrosive sublimate or chloride of platinum. They 

 agree in giving a pale red to a solution of tartar-emetic, but 



