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 which science is teaching us how to prevent or control many of our most serious diseases.
In 1896, what proved to be a very serious outbreak of plague, occurred in Bombay and spread to other parts of India. In 1898, a commission was appointed to inquire into the origin of the different outbreaks, the manner in which the disease is communicated, etc. This was known as the Indian Plague Commission, and its exhaustive report, together with the minutes of the evidence presented to the committee, represents a stupendous amount of work on this subject and is the basis for much of the later investigation that has been undertaken.