468 Scientific Intelligence. [Due. 



neither of these are in the requisite proportions. The escape of 

 the acid by heat seems to indicate the presence of a portion of 

 water amounting to about two-thirds of the loss stated as sus- 

 tained in the analysis. 



II. Polychroite. 



This is the name given by Bouillon Lagrange, and Vogel, to 

 the colouring matter of saffron, formerly considered by chemists 

 as extractive, but which they conceive to be a peculiar vegetable 

 principle. To obtain it, we have only to digest saffron in water, 

 evaporate the liquid to the consistence of a thick syrup, and 

 digest this residue in alcohol. When the alcohol is evaporated, 

 polychroite remains behind in a state of purity. The properties 

 of this substance are as follows : — 



1. It has a very intense yellow colour. Its taste is bitter, 

 similar to that of saffron, and it has an agreeable smell. 



2. It dissolves readily in water and alcohol, but scarcely in 

 ether, and not at all in fat and volatile oils. 



3. When the solution of polychroite is exposed to the light, it 

 gradually loses its colour. Its colour is destroyed likewise by 

 oxymuriatic acid. The addition of a few drops of sulphuric acid 

 changes its colour to an intense and beautiful blue. Nitric acid, 

 added in like manner, renders it green. 



4. It combines with lime, potash, and barytes, forming with 

 these bases soluble and insoluble compounds. 



5. When sulphate of iron is dropped into a solution contain- 

 ing it, a dark brown precipitate is formed. 



6. It stains cloth of an intense yellow colour. 



7. When distilled it yields an acid liquid, a yellow-coloured 

 oil, and carbonic acid gas, and carbureted hydrogen gas. The 

 acidulous liquid contains ammonia. The charcoal, when inci- 

 nerated, leaves traces of carbonate, sulphate and muriate of 

 potash, of carbonates of lime and magnesia, and of iron. See 

 Ann. de Chim. vol. Ixxx. p. 198. 



III. Picrotoxine. 



This is the name given by M. Boullay to a peculiar substance 

 which he extracted from the Coccuhis Indians, to which that 

 body owes its deleterious qualities. Picrotoxine may be obtained 

 by the following process. Boil the seeds deprived of their peri- 

 carp in a sufficient quantity of water. Filter the decoction, and 

 precipitate it by acetate of lead. Then filter again, and evapo- 

 rate slowly to the consistence of an extract. Dissolve this 

 extract in alcohol, and evaporate the solution to dryness. Repeat 

 these solutions in alcohol and evaporations, till the residue is 

 wholly soluble in alcohol and water. It then consists of picrot- 

 oxine mixed with a little colouring matter. Agitate it with a 



