67 



precipitated witli alcoholic acetate of lead: the filtered liquid is 

 freed from the surplus of lead by sul])huret of hydrogen, decolour- 

 ised with animal charcoal and allowed to evaporate spontaneously. 

 — White, wai'ty mass; has a A^ery bitter taste when dissolved in 

 cold water; fuses at 175°, and decomposes in higher temperatures; 

 dissolves in 848 parts cold, in 500 parts at 45°, and in 222 parts 

 boiling water, in 3^ parts cold alcohol of 0-85, in 21/5 to 2^ 

 l)ai"ts at the boiling heat; in 1960 parts cold, and in 1470 parts 

 boiling ether; changes into sugar, and a resin wlieir boiled with 

 diluted acids. 



Di«italic Acid, Xou- Volatile. In Digitalis purpurea. Eva- 

 porate the aqueous infusion of the leaves to syi'up-consistence, add 

 alcohol of 92°/^ as long as a precipitate ensues, filter after a few 

 days, distil off the alcohol and evaporate to the consistence of 

 thick honey. Exhaust the latter with several changes of hot 

 ether until it has nearly lost the bitter taste whereby digitalin or 

 an allied substance and Digitalic acid are dissolved. Add to the 

 ethereous tinctures by degrees, caustic bai-yta until alkaline, collect 

 the yellow deposit, wash with ether until it has lost the bitter 

 taste, afterwards with alcohol until the latter passes ofl" colourless 

 and decompose (the deposit) under water with (best an insufficient 

 quantity of) diluted sulphuiic acid. Evaporate the reddish, very 

 acid, filtered licpiid as much as possible under exclusion of the air, 

 allow to stand cold, decant from Ijrown flocks that will have sub- 

 sided, precipitate any traces of Digitalate of baryta with alcohol of 

 95%, and evaporate the filtered liquid in a vacuum. The crystals, 

 obtained from the brown mother-ley, are recrystallised in alcohol, 

 if possible under exclusion of the air. — White needle-like crystals 

 of not uni^leasant acid taste, and of faiirt peculiar smell; fuses by 

 heat, and is decomposed afterwards; changes also readily under the 

 influence of light and air, especially in the presence of alkalies ; 

 dissolves most readily in water and alcohol, less in etlier. The 

 salts of the alkalies, alkaline earths and of zinc oxyd dissolve in 

 water. 



Di»itjllic Acid, Volatile = Cio H9O 3 -f HO (of the same atomic 

 comj^osition as valerianic acid). In Digitalis purjiurea. Distil 

 the herb with water, saturate the distilled liquid with carbonate 

 of soda, evaporate to dryness, dissolve in a little water, add oxalic 

 acid and distil. The acid is floating on the distillate as a colourless 

 oil of strongly acid reaction, smells like the biaiised herb, faintly 

 resembling valerianic acid, of disagreeable taste, forms Avith lead 

 oxyd a crystallisable salt, soluble iii water. 



Di«1talill=:C50 H48 O2S (according to Walta). Occurrence 

 like Digitaletin. Exhaust the pulverised herb with water in a 

 disjilacement apparatus, digest the liquids Avith lead oxyd and a 

 little subacetate of lead until the latter test ceases to cause any 



