1813.] Scientific Intelligence. 469 



very small quantity of water, the colouring matter is dissolved, 

 and the picrotoxine separates in small crystals. Its properties 

 are as follows : — 



1. Its colour is white, and it crystallizes in four- sided prisms. 



2. Its taste is disgustingly bitter. 



3. A hundred parts of boiling water dissolve four parts of 

 picrotoxine, one half of which separates as the solution cools. 

 The solution does not alter the colour of vegetable blues. 



4. Alcohol of the specific gravity 0*810 dissolves the third of 

 its weight of this substance. A little water throws down the 

 picrotoxine ; the addition of a greater quantity redissolves the 

 precipitate. 



5. Sulphuric ether of the specific gravity 0*700 dissolves only 

 0*4 of picrotoxine. 



6. It is insoluble in oils, both fixed and volatile. 



7« Diluted sulphuric acid does not act upon it* concentrated 

 acid dissolves it, assuming a yellow colour. When heat is ap- 

 plied, the picrotoxine is charred and destroyed. 



8. Nitric acid dissolves it without the disengagement of 

 nitrous gas. The solution is yellowish-green. When heat is 

 applied, the picrotoxine is converted into oxalic acid ; but about 

 18 parts of nitric acid are requisite to produce this effect. 



9. Muriatic, oxymuriatic, and sulphurous acids, have no 

 action on it. 



10. Acetic acid dissolves it readily. Carbonate of potash 

 precipitates it from this solution unaltered. 



11. Potash, soda, and ammonia, diluted with ten times their 

 weight of water, readily dissolve picrotoxine. 



12. When triturated with potash, it assumes a yellow colour, 

 but does not emit the odour of ammonia. 



13. When heated, it burns without melting, or giving out 

 flame, exhaling a white smoke, which has a resinous odour. 



14. When distilled, it yields very little water and gaseous 

 products, but much yellow-coloured empyreumatic oil, and a 

 brilliant bulky charcoal remains behind. See Ann. de Chim. 

 vol. lxxx. p. 200. 



IV. Boletic Acid. 



This is a new vegetable acid obtained by Braconnot from the 

 juice of the boletus ps&tdo-igniarius by the following process. 

 The juice was boiled, filtered, and evaporated cautiously to the 

 consistence of a syrup. This syrup was repeatedly digested in 

 alcohol, the insoluble portion was dissolved in water, and preci- 

 pitated by nitrate of lead. The white precipitate thus obtained 

 was mixed with water, and decomposed by sulphureted hydrogen 

 gas. The water being now evaporated yields numerous crystals, 



