in a little summer watering-place not far
from New Orleans. It was not recognized as yellow fever, the doctors
thinking it a harmless little summer fever, of which the symptoms are
very similar.

Little by little the disease gained headway, until by the time its true
character was understood it had taken a hold on the people and had
become difficult to stamp out.

The strictest quarantine regulations were enforced as soon as the
sickness was proved to be true yellow fever, even the passengers on the
trains being inspected and closely watched before they were allowed to
pass from infected districts to those which were free from the dreaded
disease. With all the care it continued to increase, and has not yet
been controlled.

On such occasions the scientists are always very busy. While some of the
doctors are trying to cure the disease, others are busy preventing the
sick persons from carrying the contagion to other places, and others
again are occupied in trying to find the cause of the epidemic, and how
to prevent it in future.

One of the scientists who have been working to prevent the disease has
discovered the microbe which causes yellow fever, and claims that an
epidemic can in future be prevented by inoculating people with it in the
same way that they are now vaccinated for small-pox.

Small-pox was at one time a scourge throughout the world, and fearful
outbreaks of this plague would occur wherever numbers of people were
gathered together.

About the year 1718 an English lady travelling in Turkey noticed that
inoculation was practised in that country with the greatest success, and
that epidemics were greatly prevented thereby.

This lady, Lady Mary Wortley Montagu, introduced the practice into
England.

The idea was to introduce into the blood the germs of the dreaded
disease, practically giving the patient a slight attack of small-pox,
which made him proof against another attack.

Inoculation was, however, objected to, because sometimes the person
operated on took the disease in its violent form, and died from the
results.

The fact, however, remained that people who had been inoculated were not
liable to take the disease again, and so much good resulted that the
physicians were constantly seeking a means of inoculating that would
insure only a mild form of the disease.

The problem was at last solved by the great English physician, Edward
Jenner, in 1798.

He found that a form of small-pox was p