460 Lichenes of New England. 
Berzelius found to constitute almost 80 parts in the 
100, of Cetraria Islandica. In the latter there is also 
a bitter extractive matter, said by Linnzus to be pur- 
gative, which is removed by boiling; and the ac- 
count of the use of the Rock-Tripe given in Frank- 
- lin’svoyage,* shows that a great inconvenience found 
by the voyagers, in preparing these lichens for food, 
was their inability to remove a similar “ bitter prin- 
ciple, nauseous, and producing severe bowel com- 
plaints." The species of Gyrophora used by these 
travellers were GG. Muhlenbergii, Pennsylvanica, 
hyperborea, and proboscidea £. arctica, all of which 
are found in New England, and the former, which 
alone, it seems, is employed by the Indians, (and 
which, boiled with fish-roe or other animal matter, is 
“ agreeable and nutritious,") very abundantly occurs 
on the Blue Hills in Milton, and in many other sta- 
tions given in one of the former of these papers. 
We are told, however, that they preferred G. vellea, 
as “more agreeable to eat than any other of the 
preceding species." + It appears from the above, that 
in this case, a very considerable difference was found 
in the species used, two being considered agreeable 
and nutritious, while the rest not only brought on 
bowel complaints in some, but, it is further said, if 
they served to allay the appetite, “ were very ineffi- 
cient in recruiting our strength.” Yet an author 1S . 
cited by Mackenzie in his “ Travels in Iceland,” 
p. 423, as saying, that these lichens (the Gyropho- 
re), are “longe optimum in re cibaria Lichens 
* p. 173. t And see “ Kalm's Travels." 
