My object throughout has been to ascertain, clearly
and definitely, the action of the drugs employed on the
healthy body in medicinal doses, from the smallest to
the largest ; to deduce simple practical conclusions from
the facts observed ; and then to apply the drug to the
relief of the particular conditions to which its action
appeared suited.
Observations on the lower animals have been as
carefully noted as those on man, and my labours have in
this respect been amply rewarded; for I find, generally,
that for every variation in the effects of a particular drug
on man, we may expect to see its exact counterpart in
some one or other of the lower animals.