PREFACE. 1X 
stances of this sort occasioned a sudden and enor- 
mous rise in the price of opium, and a general in- 
quiry, what could be substituted for opium when 
the usual supplies should have failed. 
_ In a work like the present, although we can- 
not hope to supply all the desiderata of an indi- 
genous Materia Medica; yet it will be satisfacto- 
ry to have done something towards an investiga- 
tion of the real properties of our most interesting 
plants, and to have facilitated a knowledge of them 
in those, to whom they may be useful. In a pur- 
suit of this kind, the botanist has views even be- 
yond the physician. ‘To him it is important not 
only to know what plants have properties, that are 
eminently useful, but also to know, what are the 
properties and uses of all the plants which sur- 
round him. In proportion as inquiries of this 
sort are pursued, the natural resources of a coun- 
try become developed, and its natural disadvanta- 
ges compensated. We are told that in China ey- 
ery plant is applied to some valuable purpose, 
and there is scarcely a weed that has not its de- 
terminate use.* A learned author} observes, that 
“no writer whatever has rendered the natural 
productions of the happiest and most luxuriant 
climate of the globe, half so interesting or instruc- 
* Macartney’s Embassy, vol. ii. chap. 1. + Sir J. E. Smith. 
2 
