LICHENS. 169 
factured on a large scale in Rome, and in some 
other cities of Italy. Their employment for this 
purpose, however, did not depend upon any pecu- ‘ 
liar inherent scent, for the species used are per- 
fectly odourless, but upon their aptitude for ab- 
sorbing and retaining, for almost any length of 
time, the fragrance communicated to them. In- 
deed, several of our tree-lichens possess in so re- 
markable a degree this curious property, that they . 
are still employed in the manufacture of the most 
valuable and esteemed powder perfumes. 
Various other substances useful in the arts and 
manufactures are yielded by the lichens. The late 
Lord Dundonald discovered a method of extract- 
ing from a species of white filamentous lichen 
(Evernia prunastri), very frequent upon pines and 
oaks, a kind of gum which was extensively used in 
Glasgow during the French war, as an efficient sub- 
stitute for the expensive Gum Senegal, in calico- 
printing. When it was the absurd fashion to wear 
the hair whitened with powder, this same lichen 
was sometimes pulverized and employed, on ac- 
count of its cheapness, instead of flower or starch. 
A species of yellow shrubby lichen, like brass wire 
(Borrera flavicans), found on apple and other fruit- 
trees in Devonshire, Sussex, and other parts of 
the south of England, used to be employed in 
Norway in poisoning wolves, which were at one 
