RvAJf AND O'RioKDAN — Tinctorial Constituents of some Lichens. 101 



dyed the wool similarly, changes taking place during the process of dyeing 

 exactly the same as were observed with the salazinic acid. Hence it is 

 evident that the tinctorial properties of this lichen are due to its containing 

 scopuloric acid. 



C. — Ramalina Cuspidata Nyl. 

 Collection of the Lichen for Examination. 



This lichen, like the Ramalina scojndorum , was obtained in Howth, being 

 gathered from rocks to the north-west of the ^lartello Tower at Sutton, a 

 place well within the region named by Miss Knowles as being the locality 

 where it occurs (Sci. Proe. R. Dub. Soc, vol. xiv (N.S.), No. 6, p. 88). It was 

 identified by Miss Knowles as Ramalina cuspidata Nyl. 



Extraction vjith Ether. 



The ground lichen was extracted with ether for about 8 hours in a 

 Soxhlet apparatus. The extract gave, on concentration, a yellow crystalline 

 substance similar to the d-usnic acid got from Ramalina scopulorum., and 

 which was separated in the same way. This substance had the same melting- 

 point as the latter one, was similar to it in crystalline form, and was dextro- 

 rotatory in chloroform solution, so that it was in all probability the same 

 substance, d-usnic acid. 



Extraction inth Acetone. 



The lichen, after extraction with ether, was extracted with acetone as 

 before. The extract yielded a white crystalline substance on being treated as 

 in the cases of the other lichens. This substance was somewhat similar to 

 the salaziuic acid and scopuloric acid, but was more soluble in acetone than 

 either of them. The lichen contains about 3 per cent, -by weight of this 

 substance. 



When crystallized from acetone it forms prismatic microcrystalline 

 needles which differ from the salazinic and scopuloric acids in separating 

 from the solvent in granular masses, whereas these separate as fine powders 

 which form tiaky masses on drying. The crystals on heating appear to 

 soften about 200° 0., and then turn yellow, deepening gradually to brown, 

 and become black about 2o5'' C. or 260' C. without actually melting. Some 

 of the substance when recrystallized from alcohol was found to turn brown 

 about 230" C, and to melt with decomposition at 253° G. 



The alcoholic solution of this substance gives a violet-red colour with 

 ferric chloride, this colouration being more violet than that given by either 

 salazinic or scopuloric acid. ' - _ 



The substance dissolves in alkali, forming a pale yellow solution, which 



