sed, the epidemic stopped and the installation of a
filtration plant has prevented any recurrence of the epidemic.

In 1880, a severe epidemic occurred in Lowell, Massachusetts, and was
traced to an infection of the river from which the city's water-supply
was taken. This was definitely shown to have come from a small tributary
of the Merrimac River, and the particular infection responsible for the
epidemic was traced to a small suburb named North Chelmsford, where one
case of typhoid fever occurred in a factory, the privy of which was
located directly on the bank of the small tributary.

In 1900, an epidemic of typhoid occurred at Newport, Rhode Island,
through the pollution of a well, and about 80 persons were affected,
most of whom lived within a radius of 300 feet of the well and all of
whom used the well water. The well was a shallow one with dry stone
sides and a plank cover, and surrounding the well were about 20 privies,
the nearest one only 25 feet away. The water in the well was 2 feet
below the surface of the ground. It was found that a month before the
epidemic broke out, there had been cases of typhoid fever in houses
adjacent to the well, and that discharges from the typhoid patients
found access to the privy vault which was only 25 feet from the well. It
was practically certain that the well was infected by the leechings of
these privies, particularly from the one only 25 feet away.

[Illustration: FIG. 77.--Spring infected by polluted ditch.]

Another example of the way in which underground waters, such as springs,
may become contaminated is described by Whipple as occurring at Mount
Savage, Maryland, in 1904. Through this village ran a small stream
known as Jennings Run, which was grossly contaminated with fecal matter.
In July, 1904, a woman who had nursed a typhoid patient in another town
came home to Mount Savage, ill with the disease. She lived in a cottage
on the hillside above the stream, and the drainage of the cottage was
conveyed through an iron pipe onto the ground just above the stream.
Figure 77 (after Whipple) shows the relative positions of the cottage
and stream. Heavy rains occurred during the first week in July which
probably washed the infectious matter from the ground into the ditch and
then through the ground into a spring just below down the slope. A week
afterwards twenty workmen who had been drinking water from the spring
came down with the fever and new cases occurred daily for