RvAN AND O'RioRD AN — Tinctoriol Constituents of some Lichens. 93 



These lichens then, being available in fairly considerable quantity, and, 

 at least one of them, having been used for dyeing in the West of Ireland, 

 their examination was undertaken with the same end in view as in the ease 

 of the Parmelia saxatilis. 



The lichens — Parmdia saxatilis Ach., Ilamalina scopulorum Ach., and 

 Samalina cvspidata — have all been examined previously (0. Hesse, Journ f. 

 pr. Chem. (2) 62 (1900), pp. 430-477 ; ibid. 68 (1903), pp. 1-71 ; W. Zopf, 

 Liebig's Annalen, 295 (1897), p. 222 ; ibid. 352 (1907), pp. 1-44), but neither 

 Hesse nor Zopf makes any allusion to the fact of their having been used in 

 dyeing, or of their containing any substances possessing tinctorial properties. 

 Further, according to Hesse (Journ. f. pr. Chem. 1898 (2), 58, pp. 465-561), 

 the constituents of lichens are not definite for a definite species, but depend 

 to a certain extent on the place of growth, climate, and season. Thus he 

 states that Parmelia caferata when grown on limes, rocks, or walls contains 

 d-usnic, capraric and caperatic acids, whilst specimens collected from oaks 

 contain caperin and caperidin in addition ; Xanthoma parietina usually 

 contains physeione, but this is absent when the lichen has grown on pines 

 and atranorin is present instead ; Parmelia perlata from Germany contains 

 atranorin only, whereas that from America contains vulpic and usnic acids, 

 and that from India perlatiu and lecanoric acid in addition. 



Ujrperimental. 



The method employed in the examination of these lichens was to extract 

 the ground lichen in a Soxhlet apparatus with various solvents. 



The Parmelia saxatilis, which was the first of the three to be examined, 

 was subjected to a much more detailed examination than the others, as a 

 result of which it was found that by extracting the lichen first with ether 

 and then with acetone the main, and practically the only, tinctorial con- 

 stituent was extracted by the acetone, and that further extraction with 

 other solvents removed no appreciable quantities of substances. 



The other two lichens were extracted first with ether and then with 

 acetone, and, as in the case of the Parmelia saxatilis, it was found that the 

 main tinctorial constituent of the lichen was, in each case, extracted by the 

 acetone. 



A. — Parmelia saxatilis Ach. 



1. Extraction, icith Ether. — The ground lichen (about 70 grams) was 

 extracted with ether in a Soxhlet apparatus for about ten hours. The 

 extract consisted of about two parts — a colourless crystalline substance («), 

 mixed with a dark-coloured oily substance {h), 



[P2] 



