LICHENS UNDER THE MICROSCOPE. 665 
of the holes was of a grayish color, but there were no remains 
of insects and no cast skins of the spider. Before opening 
the holes we sounded them with straws and tried to provoke 
the spiders to come out, but they took no notice of it. The 
drawing represents the ring of leaves and sticks, a section of 
the tube, and the spider at the bottom, all of the natural size. 
LICHENS UNDER THE MICROSCOPE. 
BY H. WILLEY. 
Tue Lichens, though among the lowest, are also among 
the most abundant and widely distributed orders of plants. 
They are the earliest to 'cover the naked rocks with vegeta- 
tion (though none, that we are aware, have been found in a 
fossil condition), and by their decay, to prepare a soil on 
which more highly organized plants can flourish. In the | 
Arctic zone some species are so abundant as to furnish the 
reindeer with the food necessary for his subsistence, and are 
even used as fodder for cattle and swine, and are said to in- 
crease the quantity of milk. Recently they have been used 
for the manufacture of brandy—a very poor use to put them 
to—and were formerly much employed in dyeing. Hoff- 
man, in his work on the uses of lichens, gives plates of over 
seventy-five tints obtained from them. But the recent sci- 
entific discoveries in this art, have greatly diminished their 
use for this purpose. Some were formerly used for medical 
purposes, frequently in accordance with the old doctrine of 
signatures.  Peltigera canina was supposed to cure hydro- 
phobia; Sticta pulmonaria, the consumption, ete. But they 
are now considered of little, if any importance, in medicine. 
Arctic travellers have found in Umbilicaria, called ripe de 
roche, a poor and bitter substitute for food, when nothing 
AMER. NATURALIST, VOL. IV. 84 
