On the Boa Constrictor, 305 



solved in diluted nitric acid, and the heat continued for a short 

 time after the solution had been boiled to dryness , besides the 

 pink substance which lined the sides of the glass, there remamed 

 a yellow substance in appearance like bees wax. By submitting 

 the excrement to destructive distillation, a yellow substance some- 

 what similar to the preceding sublimed in the neck of the retort. 

 The yellow substance obtained by sublimation had at first an un- 

 pleasant smell, which it lost by exposure to the air for a few hours, 

 and which arose from the presence of a little foetid oily matter. 

 Its taste was pungent and peculiar. It was soft and easily fran- 

 gible. It was volatile. It was soluble in water, in alcohol, in 

 acids and in alkalies, by the agency of heat, but it was not pre- 

 cipitated from its alkaline solutions by muriatic acid. This yel- 

 low substance in a dry state did not affect moistened htnms pa- 

 per, but when dissolved in warm water it reddened litmus. In 

 most of its properties, this substance seemed to resemble Scheele's 

 sublimate from the uric acid, described by Dr. Henry in his me- 

 moir on this acid*. 



6. The fixed alkalies, in a concentrated state by the agency of 

 heat, are capable of dissolving the excrement, and during the so- 

 lution the odour of ammonia is exhaled. The alkaline solutions, 

 when treated with muriatic or sulphuric acid, afford a white or 

 yellowish white precipitate, which is either in small shining la- 

 minae (in appearance like the benzoic acid), or in minute pris- 

 matic crystals. This precipitate has a soft greasy feel, is very 

 slightly soluble in hot water, and dissolves readily and with effer- 

 vescence in nitric acid. The nitric solution, when evaporated 

 to dryness, leaves a yellow residuurti, which when treated with a 

 drop of ammonia instantly assumes a fine pink colour. Hence, 

 the precipitate in question appears to be the uric acid. And in 

 one experiment, in which I dissolved 10 grains of the excrement 

 in pure potash, I obtained, by the agency of muriatic acid, one 

 grain of uric acid. 



7. The excrement by destructive distillation furnished a variety 

 of products. The following results we obtained from 10 grains 

 heated to redness for about a quarter of an hour, in a little re- 

 tort over mercury, viz. about 6 cubic inches of gas ; 1^ grain of 

 yellow sublimate (51) ; 1 j grain of brownish sublimate impreg- 

 nated with a foetid oily matter, and 3 grains of black coaly mat- 

 ter. The gas was not accurately analysed ; but from a slight ex- 

 amination it appeared to be a mixture of nitrogen, ammonia, and 

 carburetted hydrogen. It had a foetid ammoniacal odour, about 

 one-sixth of it was readily absorbed by water, a small part of the 

 residuum was inflammable, and the remainder extinguished a 



* Memoirs of the Literary and Philosophical Society of Manchester, vol. ii. 

 Vol. 54. No. 258. Oct. 1819. U lighted 



