ful manner, the whole nervous
system, and produces greater effects in an instant, than the most
powerful cordials or stimulants received by the mouth would produce
in a considerable space of time. Hence in syncope or fainting, in
order to restore the action of the body, we apply volatile alkali, or
other strong odorous substances, to the nostrils, and with the
greatest effect. It may indeed for some time supply the place, and
produce the effects, of solid nutriment usually received into the
stomach We are told that Democritus supported his expiring life,
and retarded, for three days, the hour of death, by inhaling the
smell of hot bread, when he could not take nutriment by the stomach.
Bacon likewise gives us an account of a man who lived a considerable
time without meat or drink, and who appeared to be nourished by the
odour of different plants, among which were garlic, onions, and
others which had a powerful smell. In short, the stimulus which
active and pleasant odours give to the nerves, seems to animate the
whole frame; and to increase all the senses, internal and external.

The perfection of the organ of smell is different in different
animals; some possessing it very acutely; others on the contrary
having scarcely any sense of smell. We may in general observe that
this sense is much more acute in many quadrupeds than in man: an in
them the organ is much more extensive: in man, from the shape of the
head, little opportunity is given for extending this organ, without
greatly disfiguring the face. In the dog, the horse, and many other
quadrupeds, the upper jaw being large, and full of cavities, much
more extension is given to the membrane which is the organ of smell,
which in some animals is beautifully plaited, in order to give it
more surface. Hence a dog is capable of following game, or of tracing
his master in a crowd, or in a road where it could not be done by the
mere track. Nay, we are told of a pickpocket being discovered in a
crowd, by a dog who was seeking its master, and who was directed to
the man by the pocket handkerchief of his master, which the
pickpocket had stolen. In dogs the sense of smell must be uncommonly
delicate, to enable them to distinguish the way their master has gone
in a crowded city.

The habit of living in society, however, deadens this sense in man as
well as taste; for we have the advantage of learning the properties
of bodies from each other by instruction, and have therefore le