Intelligence and Miscellaneous Aiticles. 77 



These experiments seem to prove that the acid contained in aco- 

 nite has the same composition as maleic and fumaric acid; that is 

 to say, in its free state, like them, the composition is the same as 

 that of malic acid combined with bases, that it consists of equal 

 atoms of hydrogen, carbon, and oxygen, and is distinguished from 

 malic acid in a state of combination by containing an atom less of 

 water. 



The author states the difference between the properties of the 

 aconitic, maleic, and fumaric acids : aconitic acid does not, like 

 malic acid, yield regular and distinct crystals ; it assumes the state 

 of a crystalline crust or of mammellated masses, formed of crystals 

 so small that their form cannot be determined even by the micro- 

 scope. When pure, aconitic acid is perfectly white, unalterable in 

 the air, and very soluble in water at all temperatures, it dissolves 

 also very well in alcohol and in aether.; by evaporation it separates 

 from its solutions in thick crusts, or in fine ramifications. In this 

 respect it diff^ers from fumaric acid, which is very slightly soluble, 

 and from maleic acid, which crystallizes in very distinct prisms. As 

 to its flavour, the paramalleic acid has a disagreeable nauseous taste, 

 which aconitic acid does not possess. When exposed to heat these 

 acids act in a very dift'erent manner, and may be readily distinguished ; 

 fumaric acid fuses with difliculty ; when heated to above 392° Fahr., 

 it is completely volatilized, and yields a solid sublimate. Maleic acid 

 fuses at 248°, distils perfectly, and if the heat be raised a little, and 

 the opei-ation prolonged, it is converted into fumaric acid ; when, 

 however, it is quickly heated in a retort it is volatilized in a liquid 

 state, yielding a little fumaric acid, and on cooling, the liquid product 

 crystallizes. 



Aconitic acid acts differently when heated on a sand bath in a 

 long tube to 266** Fahr. ; it becomes brown, but does not fuse. At 

 this heat it begins to melt, but it does not boil till heated to 320° 

 Fahr., and then it becomes red-brown. If it be kept for some time 

 in this state, it is not converted into fumaric acid, but small colour- 

 less drops are observed to condense on the surface of the brown 

 liquid, which on cooling become colourless prismatic crystals ; Imt 

 the greater part of this acid is converted into a brown tenacious hy- 

 grometric matter, which dissolves in water and does not crystallize. 



Aconitic acid subjected to a sudden heat in a small much-inclined 

 retort, fuses, becomes brown, yields white vapours which condense 

 into a bright yellow liquid, of an acrid taste and emj)yreumatic 

 smell. Charcoal remains in the retort, hut the bright yellow liquid 

 Ijecomes full of slender ])rismatic crystals; when these are separated 

 more crystallize in the mother water. These crystals are not aco- 

 nitic acid ; when jirecipitated by acetate of lead they give a fioccu- 

 lent i)recii)itate, wliich differs from aconitate of lead by its greater 

 solubility ; tlie precipitate resembles those ()1)tained witii the maleic 

 and malic acids, in being converted into lirilliant crystals by contact 

 with water, which is not the case with aconitate of lead. 



Journal dc I'hurmuc'tc, vol. xxiv. j), 403. 



