THE MEDICINAL PROPERTIES OF TREES. 245 
sicians and pharmacists. Many efforts, some of which 
have been exceedingly elaborate, have been made at such 
a classification, but while each may be tolerably well 
adapted to the special need desired, none has yet been 
made which is adapted to the requirements of all. For 
instance, the classification made by the botanist has 
nothing especially to commend it to the pharmacist, who 
has chiefly to do with the physical properties of drugs ; 
while such a one as may be suited to the needs of either 
of these is of no value to him interested particularly in 
investigating the physiological action of drugs. JInas- 
much, moreover, as the therapeutical properties of medi- 
cines cannot be predicated with absolute safety in either 
their botanical, chemical, or physiological peculiarities, 
the practical physician requires a. classification different 
from that best suited to the needs of either of the others 
named. The necessarily brief consideration which we 
shall give of the medicinal trees of the United States is 
intended for neither of these professional callings, and 
we deem it not incumbent on us to attempt a classifica- 
tion adapted to either. Being thus freed from any obli- 
gation of the nature indicated, we shall, we think, best 
subserve the convenience of our readers by a simple al- 
phabetical arrangement of our subjects, and without ref- 
erence to any of the features selected as bases of classi- 
fication. 
Aztiges. The genus Pinus of Linneus is divided into 
three genera: Pinus, Abies, and Lariw. The Abies em- 
braces the firs and spruces, of which there are many 
varieties. Two of these, A. excelsa and A. Canadensis, 
are of especial interest, from a medicinal point of view, 
as furnishing respectively Burgundy and Canada, or 
Hemlock, pitch. Burgundy pitch is a resinous exudate 
from the stem of the .A. excelsa, or spruce fir. The va- 
riety most prized is imported from Switzerland. In its 
pure state it is quite hard and brittle, and of a yellowish- 
