Ill 



Iliciu. Bitter ingredient of the leaves of Ilex Aquifolium, only 

 known in the impure state. 



Ilixantllill - C34 H22 022- Yellow pigment of the leaves of 

 Ilex Aquifolium, scarcely present during winter, but copioiisly 

 in the hotter part of the summer. The alcoholic extract 

 is distilled, the remnant filtered and allowed to rest cold; the 

 gi'ains which will have formed after a few days are dried, washed 

 with ether (to remove chlorophyll) dissolved in alcohol, freed from 

 the latter by evaporation and addition of water, and recrystallised 

 in hot water. — Forms straw-yellow, microscopic needles, fusible at 

 198°, desti'oyed in higher temperatures ; dissolves scarcely in cold, 

 readily with yellow colour in hot water, also in alcohol, not in 

 ether; the aqueous solution turns orange with alkalies and 

 becomes colourless on addition of sulphuric acid, no further 

 change being observable even on boiling ; assumes a sap-green 

 colour with chloride of iron. 



Iiupeiatorin = Peucedanin. 



ludicau = C52 H31 NO34. Substance forming the indigo-blue of 

 Isatis tinctoria. Exhaiist the leaves in a disjilacement apparatus 

 with cold alcohol, precipitate the green tincture with a solution of 

 acetate of lead in alcohol and a little ammonia, wash the pale- 

 green deposit with cold alcohol, and decompose under water by 

 means of carbonic acid gas. The deposit becomes decoloiu-ised and 

 yields a yellow solution, which has to be freed from any dissolved 

 lead by means of sulphuret of hydrogen and evaporated over 

 sulphuric acid. — Yellow or light brown syrup-like liquid, which 

 can not be obtained dry withoiit decomposition, has a slightly 

 bitter, unpleasant taste and an acid reaction, dissolves in water, 

 alcohol and ether, is decomj^osed even by a gentle heat, even cold 

 by dikited acids, under formation of blue flocks. The formation of 

 the blue indigo is represented by the following equation: — 

 C52 H 31 NO34 + 4HO = C16 H5 NO2 +3Ci2 Hio O12 (indiglucin). 



Ill(li«'0-Mue = C16 H5 NO 2. Contained in many plants, 

 especially those of the genera Indigofera, Isatis and Polygonum, 

 but is only formed on drying. Plants, turning blue on drying, 

 ^re known also among the genera Asclepias, Croton, Galega, 

 Marsdenia, Mercurialis, Nerium, Phytolacca, and Pimelea, and 

 should be tested for indigo-pigment. To ascertain the presence of 

 indigo, the respective green parts are extracted with warm water, 

 and the clear solution allowed to rest at a temperature not below 

 15°; the original indigo compound is decomposed by a kind of 

 fermentation, and the blue pigment subsides. — Pure Indigo-blue is 

 deep blue, assumes on rubbing a copper-red colour, is inodorous 

 .and tasteless, fuses with heat, and sublimates at 228°, mostly 

 undecomposed, in purple-red fumes, which condense to crystalline 



