TON. | 202 
TONICS. 
i cceaeee oneieatantel 
Substances which give strength to the system. 
They do this chiefly by their continued exhibition. 
I confine this definition to absolute tonics—or 
those endued with the tonic power inherent in them, 
and evinced ander any proper circumstances for 
their use. I shall not consider here, such reme- 
dies and means, as, in themselves, are any thing 
else than tonics, but which by their operation on. 
the system under certain circumstances, produce © 
indirectly an invigorating effect—in other words 
ive tone to the system. They, relatively to the con- 
dition of the body for which they have been applied, 
act eventually as ahsolute tonics do—but it would: 
create confusion of terms and ideas, and be sub- 
versive of the unity of the subject to notice any 
such as tonics. It is far from settled into any 
thing like a uniform belief, in what ways tonics — 
do act. Itis in truth, after all which has been 
advanced on the subject by Gregory, Cullen, Dar- 
win, Barton, Blane, Paris and a host more—pure- 
ly speculative, whether they operate by the bitter 
principle, the astringent principle, a specific de- * 
termination on the muscular fibres, &c. &c. I 
shall enter fully into a consideration of the differ- 
_ ent theories which have been proposed on this sub- 
ject, in the lectares—in the mean while I may simp- 
jy state in these outlines, that, there is no class 
of remedies or means, the effect of which is so° 
‘Palpable, so generally understood and appreciated, 
