DR. KANE ON THE CHEMICAL HISTORY OF ARCHIL AND LITMUS. 277 
a considerable time, as, for some months, it is gradually converted into a mass of soft 
granular crystals, which by washing with strong cold alcohol may be obtained com- 
pletely white. This crystalline material constitutes the last gradation in the series 
of bodies arising from erythryline, and as indicative of its position, I propose to dis- 
tinguish it by the name Telerythrine. The word tcAoc indicating the termination, as 
the word v\ v indicated the commencement, of the series. 
There are thus found either pre-existing in the lichen Roccella Tinctoria, or produced 
immediately by the processes employed in its analysis, the following bodies : 
1st. Erythryline. 
2nd. Erythrine. Pseudo-erythrine of Heeren. 
3rd. Erythrine-bitter. 
4th. Telerythrine. 
5th. Roccelline, roccellic acid of Heeren. 
Generally speaking, these substances are identical with those found by Heeren in 
the Parmelia Roccella and the Leucanora Tartarea ; the ultimate production of tele- 
rythrine having escaped his notice, and, as I believe, his erythrine having been ery- 
thryline in an impure form mixed with other substances. 
It is singular, however, that these substances are all different from those found by 
Robiquet in the Variolaria dealbata. I could not find in the lichen I examined a 
trace of variolarine or orcine, and certainly the Variolaria could not have contained 
either erythryline or erythrine without their having been recognized by Robiquet. 
We may consequently infer that there exist in the lichens which yield purple colours 
at least two groups, characterized by different active principles, but, as shall be here- 
after shown, ultimately generating by their decomposition the same coloured sub- 
stance; the archil from these various lichens being for the purposes of the arts iden- 
tical, and containing in reality the same substance, orceine. 
The lichen which has been exhausted by boiling alcohol and has furnished the sub- 
stances above described, yields to boiling water only a small trace of starch and 
gummy matter. What then remains is merely woody fibre and some earthy salts. 
I shall now proceed to the description of the properties and constitution of these 
substances in detail. 
I. Of Erythryline. 
This substance when first prepared, and particularly when the preliminary opera- 
tions are rapidly conducted, is of a pale yellowish colour, often nearly white, which 
colour I consider, from the appearance of the plant, it should have if completely 
pure. It is more frequently, however, of a greenish tinge, arising, as I believe, from a 
very minute trace of chlorophyl, which attaches itself to it and accompanies it in all 
its reactions. From this trace of chlorophyl I do not know any mode of freeing it, 
but the quantity is so minute that I did not find specimens of erythryline of very dif- 
ferent shades to differ from one another in composition in a greater degree than 
might and frequently does occur in different analyses of the same pure substance. 
