ARCHIL. yjl 



or produced by the action of re- agents upon principles existing 

 in it. 



1. Erythrilin, C 32 H 16 O 6 ; a white powder, insoluble in water, 

 but converted by ebullition into erythrilin bitter, soluble in 

 alcohol and ether, also in alkaline liquids, from which it is pre- 

 cipitated by an acid ; not volatile. 



2. Erythrin, C 20 H 13 O 9 ; sparingly soluble in cold water, but 

 very soluble in boiling water, and separating on cooling in 

 brilliant, micaceous, snow-white scales ; the solution is colour- 

 less, but in air becomes rapidly brown, and is decomposed. It 

 is very soluble in alcohol, ether and alkaline solutions, from 

 which it is precipitated unaltered by an acid. It fuses at 

 220 without losing water, and is decomposed at a higher tem- 

 perature without volatilising. This substance agrees in compo- 

 sition and properties, and is believed by Dr. Kane to be iden- 

 tical with the pseudo-erythrin of Heeren, derived from the 

 Parmelia roccella. It forms a wine-red solution when exposed 

 to the conjoint action of ammonia and air. 



Erythrin bitter, amarythrin, C 22 H 13 O 14 ; is formed when 

 erythrin is dissolved in hot water and exposed some days to the 

 action of air. It is a bitter extractive matter, very soluble in 

 water, much less so in alcohol, and not at all in ether. It is 

 precipitated, like the preceding compounds, by a salt of lead. 

 This is the erythrin bitter of Heeren. 



4. Telerytrin, C 22 H 9 O 18 ; formed when amarythrin, in a 

 semi-fluid state is exposed for several months to air, the latter 

 changing gradually into a mass of very minute granular crys- 

 tals, of a brownish yellow colour, but becoming white when 

 purified by crystallization from alcohol. 



The ordinary archil (orseille) of commerce is prepared from 

 the Parmelia or Roccella. The lichens are reduced to a pulp, 

 and treated with impure ammoniacal liquors. The complete 

 production of archil requires a considerable time, and from 

 Dr. Kane's observations, the colouring matter is in a constant 

 state of transition. 



Orcin (cr.), C 18 H 12 O 8 ; a colourless crystallizable substance, 

 obtained by Robiquet from the Lichen dealbatus. The dried 

 lichen is boiled with alcohol, the solution filtered hot, and dis- 

 tilled to the condition of an extract; the last is exhausted 

 by water, and the concentrated solution brought by evaporation 



