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At the termini of the Panama railroad, Colon and Panama, Yellow fever 
is present. It has been reported at the termini of the Mexican Isthmian 
Interoceanic Railway at Tehuantepec and Coatzacoalcos. At Port Limon and 
San Josd, the terminals of the Costa Rican Interoceanic Railroad, no cases 
have been reported this year. With the completion of the Guatemalan and 
Honduranian railroads there will be at least five interoceanic railways which 
may readily serve as distributors of Yellow fever from the Atlantic side to 
the Pacific side, and conversely, perhaps, for the introduction of plague from 
the Pacific to the Atlantic side. There is every reason, therefore, why 
international action should be taken to minimise in time the risk of the 
distribution of these diseases. Further instances of the spread of Stegomyia 
and Yellow fever is given by Drs. Parker, Beyer and Pothier of the recent 
Yellow fever working party at Vera Cruz, 1903. During the construction 
of the railway connecting Vera Cruz with Mexico City, Yellow fever broke 
out amongst the employes ; at the time it was unknown in the interior, 
but was endemic at Vera Cruz. Some nine years previous to 1903, Yellow 
fever had broken out for the first time at Cordoba, and had become epidemic 
3.000 feet above sea level. Three years ago the fever appeared at Orizaba 
and became epidemic in 1902. These epidemics they attributed to the 
gradual distribution of the Stegomyia. Along the line of Mexican inter- 
oceanic railway they have demonstrated that the Stegomyia has been 
ascending from station to station until it has reached Corosal, 3,000 feet 
above sea level. — Following the ascent of the mosquito, Yellow fever has 
broken out in these places. Jalapa, on the other hand, a city of some 
35.000 people, and 20 miles beyond Corosal and at an elevation of 
4,500 feet, is free, and Yellow fever has not appeared there, although cases 
have been sent there from Vera Cruz and intermediate stations. 
The Interoceanic Canal and the Distribution of Yellow Fever. 
The experience of the French attempt to construct the Panama Canal 
demonstrates the rapidity with which Yellow fever followed the workmen. 
At the present time it will only be by the exercise of the most vigilant anti- 
Yellow fever sanitation that Yellow fever will be extinguished, and that any 
possible risk of infecting Asia, on which Sir Patrick Manson lays such 
stress, will be prevented. 
