INTRODUCTION. 
Botany, from the Greek Borivvi (a branch of which is to 
form the subject of the present work), in the more extensive 
sio-nification of the term, is that science which treats of the 
elements, the immediate principles, the internal and external 
structure, the functions, the organs, and the similitudes and 
dissimilitudes of the multitude of beings which constitute the 
vegetable kingdom : in its more limited sense, it is that science 
which teaches us to compare, to describe, and to name plants ; 
and to class them according to the mutual affinities which are 
indicated by their external characters. Sir James Smith 
divides Botany into three branches— Ist. the physiology of 
plants 2dly. the systematical arrangement and denomination 
of their several kinds, and 3dly. their economical or medical 
properties. Medical Botany is the application of the science 
to the purposes of medicine, or in other words, it is the 
botanical description and chemical analysis of those plants 
■which hav€ been found to possess medical properties, and 
which are now used in the healiiig art. From this definition 
of the term, it is obvious that a knowledge of vegetable 
chemistry is indispensable to the student, who would wish to 
make himself thoroughly acquainted with this important 
science ; but as chemistry in all its branches, forms a neces- 
sary and distinct part of a medical education, we shall in the 
present work confine ourselves, for the most part, to the 
Descriptive Botany, and the sensible properties and action on 
the human frame of those plants, which are now generally 
received in the Pharmacopoeias of the Colleges ; premising, 
at the same time, that, when treating of plants, whose chemical 
analysis it ipay be important to give, we shall use the terras of 
that science with a presumption that the student is already 
acquainted with them. 
If we confine the term Medical Botany to the mere descrip- 
tion of a plant, with a detail of its properties and actions on 
