RvAN AND O'RiORDAN — Tinctorial Constituents of some Lichens. 97 



it in that its solution in alkali gives a colourless crystalline precipitate 

 (of protocetraric acid) on acidification, whereas our substance gives a red 

 precipitate. In one respect only does our substance resemble fumaroproto- 

 cetraric acid rather than salazinic. Hesse states (Journ. f. pr. Chem. (2) 70 

 (1904), pp. 449-502) that fumaroprotocetraric acid when heated above 

 260° C. gives a sublimate of funiaric acid, which would correspond to the 

 sublimate given off when our substance is heated ; no such observation is 

 recorded in the case of salazinic acid. The formula given to the fumaroproto- 

 cetraric acid by Hesse, Os^HsnOao (requires C = 54-93, H = 3-72), does not, 

 however, agree with the analyses of our substance, so that the latter is almost 

 certainly identical with salazinic acid. 



It may be remarked here that there was obtained no indication of the 

 presence in this lichen of the low-melting substance saxatic acid, nor of 

 atranorin. If present, both of them would have been extracted by ether, so 

 it may be concluded that they are not present, at least not to any appreciable 

 extent, in the specimen of Parniclia saxatilis Ach. which we examined. 



Treatment of the Dark Oily Substance. 



All the dark-coloured washings from the acetone and ether extracts were 

 mixed together and evaporated to a small bulk. The residue, which was an 

 almost black, oily substance, was found to contain a part — 



(a) soluble in benzene, and another 



(l) insoluble in benzene, but soluble in acetone and in alkali. 



(i), which was a black, oily substance, was not examined further; 



(a) was found to consist of a part soluble in potash, and a greenish oily 

 substance, insoluble in potash, and which, on examination, proved to be 

 chlorophyll. The former part was dissolved in spirit, boiled with animal 

 charcoal, and filtered, the solution on evaporation giving a brown, vitreous 



mass. 



Further Treatment of Lichen. 



After extraction with ether and acetone the lichen was extracted with 

 chloroform, and also with benzene, but neither of these solvents removed any 

 appreciable amount of solid from it. It was then treated with sodium bicar- 

 bonate, but again it was found that the latter did not extract anything from 

 the lichen. It was not examined further. 



Dyeing Experiments. 



The lichen itself, when boiled in water with an equal amount of wool for 

 six hours, colours the wool a deep reddish-brown. The exact shade of colour 



