344 THE FIGHT AGAINST YELLOW FEVER. 



unloaded the cargo and proceeded to make repairs. Presently some 

 cases of yellow fever developed among the workmen, the mechanics, 

 the people dwelling in the vicinity of the infected ship. From July 

 25 to August 16, 21 individuals were attacked. The epidemic of 

 which the Anne-Marie was the center spread to the neighboring 

 vessels, and 10 new cases broke out more or less tardil}^ after they 

 had left port. 



England is in the same condition as France in respect to yellow 

 fever. The ports of Falmouth, Southampton, and London have had 

 several outbreaks of the disease. Epidemics may originate on a con- 

 taminated ship, carrying in its hold some Stegomyia. These in- 

 sects, either infected when the ship sailed or susceptible of infection 

 from yellow-fever patients during the voyage, transmit the disease to 

 whoever ap})r()aches them. Some moscpiitoes pass to ships near by 

 and make them new centers of the disease. That is the story of the 

 epidemic of Saint-Xazaire in 1S()1. It is likewise the history of the 

 epidemic that occurred four years later at Swansea, England, where 

 the ship Ileehu arriving from Cuba, contaminated a score of persons 

 coming aboard and spread the fever to another vessel anchored in 

 its vicinity. 



This is not the place to give a story in detail of all epidemics. It 

 is enough to say tliiit all the particular circumstances are clearly 

 explained l)v the supposition that the mosquito is the sole agent of 

 propagation of the infectious germ and by the knowledge of its mode 

 of life, its habits, and its dwelling places. 



11. 



What has been said of the geographical distribution of yellow 

 fever has shown the tendency of the disease to spread continuously 

 on land. It is seen that its progress has been steady since the begin- 

 ning of the sixteenth century. Can we tell where its onward march 

 will stop unless scientific hygiene intervenes to cut it short ? Should 

 we suppose that it Avill continue indefinitely and that tlie pest with- 

 out cessation will overrun new regions as navigation is developed 

 and as conmiercial relations are multijdied with contaminated coun- 

 tries? Finally, what are the countries menaced in the more or less 

 near future? 



It is easy to answer these ijuestions. It is enough to translate the 

 statement into a language conforming to the doctrine of propagation 

 of the disease by the mosquito. Tlw yellow fever will be implanted 

 wherever the Stegomyia lives and nudtiplies, or better, wherever it 

 is capable of living and multiplying. By a happy chance for Euro- 

 pean countries it is found that this species of mosquito can live only 

 in conditions of high temperature, exactly adapted to the accomplish- 



