460 SA NTALIC ACID. 



now separates, purified by repeated crystallization from 

 water. Stellate groups of colorless needles, of an in 

 tensely bitter taste. Difficultly soluble in cold water, 

 more easily soluble in hot water and in alcohol. Very 

 poisonous. Combines with alkalies, baryta, and lime, 

 forming gummy compounds, which are obtained pure 

 only with great difficulty. &quot;When boiled with weak 

 acids, it is converted into non-crystallizing, weak 

 acids. By boiling it with nitric acid, oxalic acid is 

 produced. 



Porrisic acid (Euxanthic acid), C 19 H 16 10 , in purree, 

 a yellowish coloring matter, imported from^ the East 

 Indies, probably the juice of a plant evaporated with 

 magnesia. Purree consists essentially of magnesium 

 euxanthate. The acid forms yellow, shiny &quot;prisms, 

 sparingly soluble in cold water, easily soluble in alco 

 hol and ether. Its salts, with the alkaline metals, are 

 yellow, crystallizable. The magnesium salt crystal 

 lizes particularly beautifully. With chlorine and bro 

 mine, it forms yellow-colored crystallizing acids, con 

 taining chlorine and bromine (C 19 H 14 C1 2 10 and C 19 H 14 

 Br 2 10 ). &quot;When heated to 180, it is decomposed into 

 carbonic- anhydride, water, and euxanthon, C 13 H S 4 , 

 which is also formed when the acid is dissolved in con 

 centrated nitric acid; this substance crystallizes in- 

 yellow prisms ; when melted with potassium hydrox 

 ide it yields, first euxanihonie acid, C 13 H 10 5 , at a higher 

 temperature hydroquinone (p. 303). 



ftuassin, C 10 II 12 3 , the bitter ingredient in the wood 

 of Quassia amara and excelsa from South America. 

 Fine, colorless, crystalline laminae, of an exceedingly 

 bitter taste ; but slightly soluble in water, easily soluble 

 in alcohol ; fusible, solidifying in a resinous state. 



Santalic acid (Santalin), C 15 H 14 5 , in sandal wood 

 (from Iterocarpus santalinus), from which it is ex 

 tracted with alcohol. It is precipitated from the solu 

 tion with lead acetate, and the precipitate decomposed 

 with dilute sulphuric acid and alcohol. Microscopical 

 crystals, of a beautiful red ; insoluble in water, soluble 



