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ratified in February 1904, was ceded to the United States in perpetuity. Part
of the district traversed by the canal is low and swamp, part is hilly, and within
it are the main streams and tributaries of two large rivers, the Chagres and the
Rio Grande. Following the route from the Atlantic to the Pacific coasts thé
canal first passes through tropical jungle on a low swampy alluvial plain to the
Gatun locks and dam, which, by impounding the waters of the Chagres and its
tributaries, will form in the valley ' of the river an artificial lake 24 miles long
and with an area of about 164 square miles, extending to the series of nearly
continuous hills through- which the Culebra cut has been dug. At the end of
this section the canal will enter a second smaller lake formed between the
locks at Pedro Miguel and Miraflores by impounding the waters of the Rio
Grande, and afterwards it will pass down the valley of that river to Panama.
The Panama Inter-Oceanic Railroad, along which are a number of large and
small villages, follows, in general, the same route. Including employees of the
Canal Commission the population of the area over which the United States has
sanitary control is estimated to be nearly 155,000 of whom about 46,000 are in.
Panama and nearly 20,000 in Colon.
Climatic conditions on the Isthmus in this region are represented by an
average temperature which throughout the year varies less than 3° from the
annual average of nearly 8o°F, and by an annual rainfall which is about 140
inches on the Atlantic coast, about 93 inches in the interior, and about 60 inches
near the shores of the Pacific. As regards rainfall, however, there is a sharp
division into dry and rainy seasons, the dry season beginning in December and
lasting until about the middle of April. The rains of the wet season are some-
times " torrential " and widespread flooding occurs. These and other condi-
tions such as the arrangements for collecting and storing water during the dry
season, the frequent importation of large numbers of non-immunes, and the
trade communications with other ports in the endemic area, have been favour-
able to the presence of yellow fever ; and although such statistics as are
available indicate that the terminal cities were sometimes free from reported
cases for several successive years, it is believed with good reason that the disease
was constantly present in an endemic form, and that the introduction of a
sufficient number of non-immunes would, in any year, have resulted in an
epidemic. This, at any rate, was the belief in which the sanitary authorities
of the United States commenced, in the spring of 1904, to take measures for
protecting the labour force from yellow fever. The problem was concerned
almost entirely with the eradication of the disease from the cities of Panama
and Colon, and with preventing its reintroduction into them ; and the measures
taken included, in addition to a great campaign for the detection and isolation
of people suspected to be suffering from yellow fever and the thorough fumiga-
tion of every house with the object of destroying infected mosquitoes, such
measures as the establishment of complete health departments for the towns
and of quarantine arrangements for the ports, the preparation and construction
of water-supply and sewage systems, the construction, paving and draining of
streets, the demolition and rebuilding of insanitary houses, the reclaiming of
large tide-washed areas and water-logged swamps, the abolition or effective
covering of every water-receptacle in the towns, and the screening of houses.
In the early days of these admirable sanitary works the difficulties were
great. Much local prejudice had to be overcome and there was considerable
delay in obtaining necessary materials. The construction of the water-supply
system for Panama was sanctioned in August 1904, but owing to the non-arrival
of the iron water mains the work could not be completed until July 1905.
Sewers were not laid until the fall of 1905 and street paving not until the end
of that year. Mr. W, F. Johnson's book entitled " Four centuries of the
Panama Canal " contains the following passages regarding this matter : " Re-
quisitions for supplies, even for things urgently needed in the hospitals and by
the sanitary squad, in cases where every hour was precious, had to be sent to
Washington, deliberated upon by the Commissioners, and then, if approved,
advertised, awarded, and finally filled weeks and months after date. It took
many weeks to get mosquito-netting for the windows of the Canal office building
and then not enough was supplied. The chief sanitary officer wanted netting
for all the official buildings in the Canal zone. This request was refused as