DESTRUCTIVE DISTILLATION OF ANIMAL MATTERS. 577 



does not thoroughly melt, and at the same time exhales a peculiar irritating vapour, 

 due, apparently, to partial decomposition. It is insoluble in hydrochloric acid ; 

 strong nitric acid dissolves it, and the solution on boiling gives off red fumes; but 

 on the addition of water the original substance is deposited apparently unchanged. 

 Potash colours it brown, and on boiling dissolves it, giving a dark brown solution, 

 from which acids precipitate brown flocks. Ammonia, and even carbonate of 

 ammonia, produce a similar decomposition. When heated, it swells up, giving off 

 a pungent smell, and leaving a bulky charcoal. This substance has not been ana- 

 lysed, but the corresponding product of the decomposition of picoline has been 

 examined, and there can be no doubt that the two substances are of analogous 

 constitution. I shall defer any observations on this point until I come to treat of 

 the picoline compound. 



Action of Bromine on Pyridine. — When bromine water is gradually added to a 

 solution of pyridine, the fluid becomes muddy, and as the quantity of bromine 

 increases, an abundant precipitate appears, and collects at the bottom of the ves- 

 sel in the form of a reddish mass of a more or less resinous appearance. This 

 substance is insoluble in water, but soluble in alcohol and ether. When boiled 

 with water it melts and emits a pungent and irritating odour, resembling that of 

 bromine. Hydrochloric acid decomposes it, dissolving pyridine, and liberating, 

 bromine, which collects at the bottom of the fluid. Potash likewise decomposes 

 it, evolving pyridine, and combining with bromine. These characters lead to the 

 conclusion that the substance is a direct compound of pyridine, with in all proba- 

 bility, several equivalents of bromine ; but its properties were not so definite 

 as to induce me to prepare it on a scale sufficiently large for a detailed exami- 

 nation and analysis. When dry pyridine is thrown into dry bromine vapour, it 

 immediately solidifies into a crystalline mass, which dissolves in water, with 

 the exception of a small quantity of a brownish flocky matter, probably analogous 

 to the compound produced by similar treatment with chlorine. The solution in 

 water becomes dark-coloured on evaporation, and yields a syrup which solidifies, 

 on standing, into a mass of minute crystals of hydrobromate of pyridine. 



Action of Iodine on Pyridine. — When a mixture of pyridine and tincture of 

 iodine is evaporated to dryness on the water-bath, a dark brown mass is left, 

 which dissolves partially in water, leaving a quantity of brown crystals, too small 

 in amount to admit of examination, and which are very easily decomposed. 

 They appear to be a product similar to the iodine compounds of the fixed bases. 

 The watery solution contains a quantity of a brown matter, removable by animal 

 charcoal, and the fluid, on evaporation, yielded crystals which analysis proved to 

 be the hydriodate of pyridine, although not quite pure. 



| 5-774 grains dried at 212° gave 

 ( 7'673 ... iodide of silver. 



