69 



becomes brown and disappears completely. It acts as a strong 

 poison.] 



Digitoleic Acid. In Digitalis purpurea. Precipitate the 

 •extract of the leaves cold with, subacetate of lead, boil the washed 

 deposit with a solution of carbonate of soda for a quarter of an 

 hour, saturate the brown filtrate Avith an excess of diluted 

 sulphuric acid which throws down flakes that have to be collected, 

 washed, di-ied and boiled with alcohol of 85°/^. Evaporate the 

 alcoholic solution, treat the remnant of crystalline structure re- 

 peatedly with ether, and let the liquids evaporate. A green oil 

 remains, which soon solidifies into a gTanular, crystalline mass. 

 Dissolve in aqueous bicarbonate of soda, precipitate with acetic 

 acid, wash, dissolve in ether and evaporate. — Green, concentrically 

 united crystalline needles, fusing at 30°, of no disagreeable odour, 

 of bitter and acrid taste; has an acid reaction when dissolved in 

 alcohol, leaves greasy spots on paper; little soluble in water, 

 readuy in alcohol and in ether, forms with the oxyds of metals 

 insoluble yellow or green floccous salts. 



DiOSIuill. Bitter ingredient of the Buccu.-leaves (from Barosma 

 serratifolia, B. crenulata, B. betulina.) Crystallises from the 

 alcoholic tincture, is insoluble in water, dissolves in alcohol, ether, 

 volatile oils and diluted acids. 



[Ditaiuiu. Alkaloid, obtained by Jobst and Hesse from Dita-bark 

 (from Alstonia scholaris). Precipitate the aqueous decoction of the 

 bark successively with acetate and subacetate of lead, remove the de- 

 jiosit, ti-eat the liquid with sulphuret of hydrogen, filter, acidulate 

 the fiJtrate and precipitate with phospho-tungstic acid. Mix the 

 j)recipitate with excess of solution of baryta, shake with ether and 

 treat the ethereous solution of impure Ditamin with acetic acid. 

 Acetate of D. is thus obtained, which is subsequently converted 

 into the pure base. — It forms a white amorphous powder of a 

 slightly bitter taste, easily soluble in ether, chloroform, benzol and 

 iilcohol. Concentrated sulphuric acid dissolves it with i-eddish 

 colour, which becomes violet on heating. Concentrated nitric acid 

 dissolves it yellow, on gently heating dark-green, then orange-red 

 imder evolution of orange vapour. It melts at 75° to a yellow 

 liquid, which at 130° becomes deep brown- red. Dissolved in 

 alcohol it has an alkaline reaction and neutralises acids, forming 

 solutions of very bitter taste, which are precipitated, yellow by 

 chloride of platinum; imjDure yellow by chloride of gold; wliite 

 by chloride of mercury, iodide of potassio-mercury, iodide and 

 sulphocyanide of potassium, tannic and phospho-tungstic acids. 



By exhausting the Dita-bark with petroleum ether, the same 

 authors obtained EcHiCAUTSCHiNnCos H20 O2, soluble also in 

 chloroform, ether and benzol, sparingly even in boiling alcohol; 



ECHlCERINZZlCao H24 O2, ECHITIN=:C32 H2C O2, EcHITEINr: 



