places might be cited. The results have all been
practically the same. To-day the soldiers of many civilized nations are
required to protect themselves from mosquitoes because it has been found
that it pays. Disease has always been a worse terror than bullets in any
war, and we are fast learning that the great loss from diseases
heretofore considered unavoidable may be very largely eliminated by
proper sanitary arrangements and protection from noxious insects.

CHAPTER VIII

MOSQUITOES AND YELLOW FEVER

Yellow fever is a disease, principally of seaport towns, from which the
United States has suffered more than any other country. It is endemic
only in tropical regions but is often carried to subtropical, sometimes
even to temperate zones where, if the proper mosquitoes exist, it may
rage until frost.

Vera Cruz, Havana, Rio de Janeiro, and the west coast of Africa were
long regarded as permanent endemic foci, the disease appearing there in
epidemic form from time to time, often spreading to other ports in more
or less close communication with such places. In the United States the
Gulf states have been the greatest sufferers from the disease, although
it has spread as far as Baltimore, Philadelphia and Washington, where at
rare intervals it was most serious, abating its ravages only when frost
came.

The last severe outbreak occurred in New Orleans in 1905 when eight
thousand cases and nine hundred deaths occurred. At that time there was
waged one of the most remarkable warfares against death in its most
terrifying form that the world has ever known. And, thanks to the
achievements of science, particularly to the investigations of three
men, one of whom gave his life to the cause, the fight was successful
and this dreadful outbreak was checked just at the time when according
to all precedent it should have been at its height.

This result which at other times and under other conditions would have
been considered miraculous was achieved not by the usual custom of
isolation, quarantine, etc., but by a direct, we may almost say hand to
hand, conflict with mosquitoes: the mosquitoes belonging to a particular
genus and species, _Stegomyia calopus_ (_fasciata_).

Before taking up a discussion of this achievement in New Orleans let us
consider first the work of the men that made such results possible.

For many years the cause and methods of dissemination of this disease
had been a puzzle to physicians and scie