DR. KANE ON THE CHEMICAL HISTORY OF ARCHIL AND LITMUS. 285 
giving- by treatment with ammonia the wine-red substance, which is the commence- 
ment of the archil series. It is, however, the amarythrine which roost rapidly and most 
perfectly produces that result. The exact nature of the products of this interesting 
process will next be studied as they exist in the archil of commerce prepared from 
the species of lichen, the simpler changes of whose characteristic ingredients we have 
now examined. 
Section II. Chemical examination of the Archil ( Orseille ) oj Commerce. 
The archil which I made the subject of experiment, is prepared by treating in the 
usual manner by means of impure ammoniacal liquors, the lichen already described, 
previously ground down to a pulpy form. The complete production of archil re- 
quires considerable time, and indeed it will be hereafter shown, that archil is always 
in a transition from one stage to another, and that in these various conditions the 
nature of its colouring material is completely different. 
To separate the substances contained in archil, the following process was ultimately 
found the most successful. A quantity of archil was rendered slightly acid by mu- 
riatic acid, and then evaporated cautiously to perfect dryness. The dry mass was 
boiled in spirit until this came off but very slightly coloured. The alcoholic liquors 
were then all mixed together and distilled in a water bath to dryness, by which a 
deep crimson mass was obtained. This was then powdered and washed with cold 
watei until all traces of sal-ammoniac had been removed, the powder then dried and 
digested in warm sulphuric ether as long as this fluid became very sensibly coloured. 
Aftei the action of the ether, the last traces of it having been removed by exposure 
to a temperature of 212 for a couple of hours, the proper colouring substance of the 
archil remains as a fine crimson powder. Of this substance there are two different 
modifications, of which one constitutes the orceine of Robiquet and Dumas, and the 
other being very closely allied to it, I shall distinguish them by the terms Alphaorceine 
and Betaorceine, retaining the word Orceine as a kind of generic term for both. 
The ethereal solutions, which are of a fine crimson colour, are next to be distilled 
in a water bath to dryness. A semifluid mass remains, of an oily nature, staining 
paper, and liquifying completely at a moderate heat. On standing for a few days, a 
little orceine gradually separates from it, and in order more certainly to free it from 
traces of that substance, it should be dissolved in the smallest possible quantity of 
ether, the solution decanted from the powdery orceine which remains undissolved, 
and^ then evaporated, at first at a very moderate heat, but ultimately being kept at 
212° for a long time, in order to be certain that the last portions of ether had been 
expelled. . The substance thus obtained is still not always simple, but the peculiar 
characteristics of it shall be hereafter described. I give to it the name of Erythroleic 
The mass which resisted the solvent action of the alcohol should next be boiled in 
water repeatedly. At first the liquor becomes pink from traces of orceine, which 
