THE PAGE OF NATURE. 109 



of the East Indian Archipelago, St. Helena, and Mada- 

 gascar, and exhaled, when moistened, an exceedingly 

 agreeable fragrance, somewhat resembling musk or 

 ambergris. This odour it may have derived from the 

 spice trees on which it was produced. Among the 

 Arabian physicians it was once in high repute when 

 macerated in wine, as a cordial and soporific. So late as 

 the seventeenth century, some of the filamentous lichens 

 were sold in the shops of barbers and perfumers under the 

 name of Usnea, and they formed the basis of a celebrated 

 fragrant powder for the toilet, called Corps de Cypre gris 

 or Cyprio, which is still manufactured on a large scale in 

 Rome, and in some other cities of Italy. Their employ- 

 ment for this purpose, however, did not depend upon 

 any peculiar inherent scent, for the species used are per- 

 fectly odourless, but upon their aptitude for absorbing 

 and retaining, for almost any length of time, the fragrance 

 communicated to them. Indeed, several of our tree-lichens 

 possess in so remarkable a degree this curious property, 

 that they are still employed in the manufacture of the 

 most valuable and esteemed powder perfumes ; and they 

 might be turned to useful account, by the sanative com- 

 mission, in imbibing and retaining the noxious vapours 

 from cesspools and over-crowded streets, which are so 

 injurious to the health of the inhabitants of our large 

 cities their small bulk and light weight allowing of 

 their being easily removed, when thoroughly saturated 

 with the offensive effluvia. 



Various other substances useful in the arts and manu- 

 factures are yielded by the lichens. The late Lord Dun- 

 donald discovered a method of extracting from a species- 



