imagination of our Stone Age ancestors should have
personified them as demons, "attacking" or leaping upon their victims
and "seizing" them with malevolent delight. The concrete comparison was
ready to their hand in the attack of fierce beasts of prey; and as the
tiger leaps for the head to break the neck with one stroke of his paw,
the wildcat flies at the face, the wolf springs for the slack of the
flank or the hamstring, so these different disease demons appear each to
have its favorite point of attack: smallpox, the skin; cholera, the
bowels; the Black Death, the armpits and the groin; and pneumonia, the
lung.

There are probably few diseases which are so clearly recognized by every
one and about which popular impressions are in the main so clear-cut and
so correct as pneumonia. The stabbing pain in the chest, the cough, the
rusty or blood-stained expectoration, the rapid breathing, all stamp it
unmistakably as a disease of the lung. Its furious onset with a
teeth-chattering chill, followed by a high fever and flushed face, and
its rapid course toward recovery or death, mark it off sharply from all
other lung infections.

Its popular names of "lung fever," "lung plague," "congestion of the
lungs," are as graphic and distinctive as anything that medical science
has invented. In fact, our most universally accepted term for it,
pneumonia, is merely the Greek equivalent of the first of these.

It is remarkable how many of our disease-enemies appear to have a
preference for the lung as a point of attack. In the language of _Old
Man Means_ in "The Hoosier Schoolmaster," the lung is "their fav'rit
holt." Our deadliest diseases are lung diseases, headed by consumption,
seconded by pneumonia, and followed by bronchitis, asthma, etc.;
together, they manage to account for one-fourth to one-third of all the
deaths that occur in a community, young or old. No other great organ or
system of the body is responsible for more than half such a mortality.
Now this bad eminence has long been a puzzle, since, foul as is the air
or irritating as is the gas or dust that we may breathe into our lungs,
they cannot compare for a moment with the awful concoctions in the shape
of food which are loaded into our stomachs. Even from the point of view
of infections, food is at least as likely to be contaminated with
disease-germs as air is. Yet there is no disease or combination of
diseases of the whole food canal which has half the mortality of