REVIEWS. 347 
since, not only are they not identical in this respect, but again, 
because they answer to different indications. 
We ought likewise to observe, that it has been rather by 
an appeal to their primitive action, to the curative effect of 
the mercurials and the compounds of iodine, chlorine, anti- 
mony, and some other analogous medicaments, we have 
founded our sixth and seventh classes of special excitants ; 
since, in considering the primitive influence of these agents, 
whose immediate effects, always obscure, often inappreciable, 
cannot be developed in an exclusive manner under the same 
circumstances. 
To return, our constant aim, in the introduction of several 
elements of classification, has been to group medicinal sub- 
stances among them, in such a manner as to be able to offer 
to the practioner series of agents, among which he might find 
instruments with which he would have it in his power to 
modify such and such an organ, or such and such a system 
of organs, without his losing sight of the secondary effects he 
had a right to hope for. 
But a combination like this necessarily presents great 
difficulties, and we are far from flattering ourselves that we 
have succeeded in surmounting them. In fact, how are we 
to expect to range, in their precisely suitable places, those 
medical agents whose primitive action is still covered with a 
thick veil, and whose effects, altogether, according to the dose 
in which they are exhibited, the form in which they are ad- 
ministered, the state or condition of the subject at the time, 
and many other casual circumstances, are totally different. 
For all this, with such difficulties flying in our face, must 
we renounce all attempt at methodic distribution, or sub- 
stitute for it alphabetical disorder ? Persuaded that a classi- 
fication, based upon the characters of things, however 
imperfect it may prove, is still preferable to our resting upon 
words alone (when it does not run to the height of preventing 
the examination of every object with independence), we have 
not hesitated a moment in our choice, though well convinced 
beforehand that we are giving a great deal more room for 
criticism. 
XXVII. 
52 
