sharper
scrutiny. When Cullen wrote his Materia Medica, he had seriously to
assail the practice of giving burnt toad, which was still countenanced by
at least one medical authority of note. I have read recently in some
medical journal, that an American practitioner, whose name is known to
the country, is prescribing the hoof of a horse for epilepsy. It was
doubtless suggested by that old fancy of wearing a portion of elk's hoof
hung round the neck or in a ring, for this disease. But it is hard to
persuade reasonable people to swallow the abominations of a former
period. The evidence which satisfied Fernelius will not serve one of our
hospital physicians.

In this way those articles of the Materia Medica which had nothing but
loathsomeness to recommend them have been gradually dropped, and are not
like to obtain any general favor again with civilized communities. The
next culprits to be tried are the poisons. I have never been in the
least sceptical as to the utility of some of them, when properly
employed. Though I believe that at present, taking the world at large,
and leaving out a few powerful agents of such immense value that they
rank next to food in importance, the poisons prescribed for disease do
more hurt than good, I have no doubt, and never professed to have any,
that they do much good in prudent and instructed hands. But I am very
willing to confess a great jealousy of many agents, and I could almost
wish to see the Materia Medica so classed as to call suspicion upon
certain ones among them.

Thus the alien elements, those which do not properly enter into the
composition of any living tissue, are the most to be suspected,
--mercury, lead, antimony, silver, and the rest, for the reasons I have
before mentioned. Even iodine, which, as it is found in certain plants,
seems less remote from the animal tissues, gives unequivocal proofs from
time to time that it is hostile to some portions of the glandular system.

There is, of course, less prima facie objection to those agents which
consist of assimilable elements, such as are found making a part of
healthy tissues. These are divisible into three classes,--foods,
poisons, and inert, mostly because insoluble, substances. The food of
one animal or of one human being is sometimes poison to another, and vice
versa; inert substances may act mechanically, so as to produce the effect
of poisons; but this division holds exactly enough for our purpose.

Strictly speak