le before it we do not wonder that the very word filled them with
horror. One of the greatest scourges ever known began in Egypt about
A.D. 542, and spread along the shores of the Mediterranean to Europe and
Asia. It lasted for sixty years, appearing again and again in the same
place and decimating whole communities.

Another great pandemic, beginning in 1364, spread over the whole of the
then known world and appeared in its most virulent form. On account of
diffuse subcutaneous hemorrhages it came to be known as the "black
death" and of course spread terror in all the communities where it
appeared. Whole villages and districts were depopulated. The death-rate
was very high, one authority placing the total mortality at twenty-five
million.

During this time new centers of infection were established, and since
then it has been carried by the commerce of the nations to all parts of
the world. It is not restricted, as many other epidemic diseases, to the
tropics or semi-tropics, although as a matter of fact we find it is more
prevalent in these regions on account of the sanitary conditions.

HOW PLAGUE WAS CONTROLLED IN SAN FRANCISCO

Attention is called to these things in order that we may compare past
conditions with present. During the last few years San Francisco has
been fighting an outbreak of plague that in other days would have been
nothing less than a national calamity. But with modern methods of
handling it, based on knowing what it is, what causes it and how it is
spread, the authorities there have been able not only to hold the
disease in check, but practically to stamp it out with the loss of
comparatively few lives.

Dr. Blue of the Public Health and Marine Hospital Service and his
co-workers directed their whole energy toward controlling the rats. A
small army of men were employed, catching rats in every quarter of the
city. Dr. Rucker reports that fully a million rats were slain in this
campaign. Their breeding-places were destroyed by making cellars,
woodsheds, warehouses, etc., rat-proof and removing all old rubbish.
Garbage cans were installed in all parts of the city, as it was required
that all garbage be stored where rats could not feed upon it, and
altogether every effort was made to make it as uncomfortable as possible
for the rats.

The marked success attending this work abundantly confirms the soundness
of the theory upon which it was based, and serves as another example of
the way in whi