
ECONOMICAL APPLICATIONS OF BRITISH LICHENS. 287 
of Shetland, some of the “Crottles” of the Scotch, Irish, and 
Welsh peasantry, and similar native dyes in our own and other 
countries. 
5. Yellow and brown colouring matter, such as Chrysophanic 
and Vulpinic acids, which exist ready formed in the cells of the 
cortical layer of the Lichen-thallus, and are readily yielded to 
boiling water or to alcohol. Many of these have been, or are, 
applied in some parts of the Scotch Highlands, in Ireland, Wales, 
Scandinavia, America, and other countries, to the dyeing of yarn 
and home-made fabrics; one of them, Chrysophanic acid, has 
been recently proposed as a test for alkalies. 
Il. Nutritive Substances. 
a. Amylaceous matters, such as Lichenin and Inulin, which 
are essentially modifications of common starch. Hence the use 
of many species as food for man and as fodder for domestic and wild 
animals in northern gr Arctic countries; e.g. Cetraria Islandica 
(“Iceland Moss”) by the Icelanders, the Umbilicarias (‘'Tripe 
de Roche’’) by the Canadian hunter or Arctic voyager, Cladonia 
rangiferina (“ Remdeer Moss”) by the reimdeer, and probably 
Lecanora esculenta (“Manna”) by the nomade tribes of the 
steppes of Tartary. 
Ill. Medicinal Subsiances. 
a. Gummy and mucilaginous matiers. Hence the use of Cetraria 
Islandica, Sticta pulmenaria, Roccella tinctoria, and other species 
in medicine as emollients, demulcents, and expectorants, and of 
the gum of Physcia prunastri, Ramalina fraxinea, Usnea bar- 
bata, and others, as a substitute for gum-arabic and similar sub- 
stances in calico printing, weaving, paper, parchment, and paste- 
board making, ete. 
b. Bitter or astringent matters, sucht as Cetraric a Gallic 
acids, Picro-lichenine, Stictine, etc. Hence the (reputed?) as- 
tringent qualities of Physcia prunastri and furfuracea, Cetraria 
Islandica and Sticta pulmonaria; the two latter of which have 
been used in the arts (in tanning) and in medicine (as tonics) ; 
the supposed antiperiodic or febrifuge virtues of Parmelia parie- 
tina and Physcia furfuracea, and the purgative properties of 
Cetraria Islandica and several of the Umbilicariee. 
e. Various Salts, and especially Oxalate of Lime. _ Hence the 
