PART I. 2” 
| MATERIA MEDICA. 
Winer this fe ae deipte pint para 
such as are used in the cure of diseases ; to which is subjoined a 
short view of their natural, medical, and pharmaceutical history, with 
the virtues and doses of. dath. It would be an unnecessary task to 
enumerate and describe all the articles that have acquired the name 
of medicine, but I trust that a sufficient collection will be found i in 
this work, not only to subserve all the useful purposes of the physi- 
i se also to enable him to understand the nature and prope 
of most of the remedial articles now in use, even though | 
sent from the empl of them. a r 
In explaining e operations . of medicines, and caekng them ac 
cording to ee operations, it is to be regarded as a first principle. 
that they act only on the living body. The presence of life is ac- 
mpanied with peculiar properties, and with modes of action inex- 
plic on mere mechanical or chemical principles. Substances 
acting on the living system no doubt produce effects referable to 
these ; but the changes they produce are also always so far modified 
as to be peculiar in themselves, and regulated by laws exclusively 
belonging to organized matter. 
Medicines, in general, operate by stimulating the living fibre. 
This proposition cannot, however, be received in an unlimited sense. 
From the exhibition of different medicines, very different effectsare 
produced, which cannot be satisfactorily explained from the cause as- 
signed,—the difference in the degree of stimulant operation. They 
differ in kind so far, that even in the greater number of cases, one 
remedy cannot by any management of dose or administration be 
made to produce the effects which result from the action of another. _ 
It is therefore necessary to admit some modifications of the gene- 
ral principles above stated, and the following are perhaps sufficient 
to afford grounds for explaining the operations of remedies, and for 
establishing a classification of them sufficiently just and compreh 
sive. : 
de. Stimulants are not to be regarded as differing nee in, 1e 
of stimulant operation which they exert. An important dis- 
a exists between them, as they are more or less diffusible and 
at in their action. A stimulus is termed diffusible, which, © 
it is applied, or at least in a very short time after, "extends 
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