rHE FIGHT AGAINST YELLOW FEVER." 



By A. Dastre. 



Once again yellow fever claims our attention. AAliile we are cele- 

 brating the victorious eflfort of science in driving that dread disease 

 from its hereditary domains in Habana and Rio Janeiro, it reappears 

 and desolates New Orleans; it revives in Honduras and threatens 

 Panama. Once more we must fight to renew the achievements of 

 the Americans in Cuba and of the Brazilians in Rio. And that is 

 possible, for we can struggle to-day with hope, with certainty of suc- 

 cess. For centuries the disease remained unconquerable. Physicians 

 knew onl}^ what everybody sees — the external signs — the symptoms 

 and fatal results, but they were not familiar with the true nature of 

 the disease and the manner of its propagation. 



In fact, even to-day our knowledge of the nature of the evil is very 

 elementary; we have few facts concerning the micro-organism of 

 yellow fever. The only proven point is that it is a blood parasite, 

 not feeding upon the red corpuscles like the parasite of malaria, but 

 only upon the fluid part — the " plasma." It is believed that it does 

 not affect the transparency of liquids, that it can penetrate most fil- 

 ters, and that it remains invisible to the microscope. 



But if the deadly agent, the ultramicroscopic germ, which is the 

 specific cause of the disease, is not well known, we are at least familiar 

 with the means of its propagation, the sole agent of its transmission, 

 and that is sufficient, as we shall see, rationally and effectually to 

 eliminate contagion. 



This definite agent, the only one capable of inoculating a man with 

 the micro-organism of yellow fever, is a particular species of mos- 

 quito, the Sfegomyia fasciata., known also as Culex calojyus and 

 previously called Culex fasciata. At the time of Linne, in 1758, 

 only 6 species of mosquitoes were known. In 1902, 250 different 

 species could be distinguished, and the number has since increased to 

 nearly 400 described species. The English naturalist, F. V. Theo- 

 bald, an authority on the subject, recognized 29 genera. To one of 



a Trniislatecl from Revue ties Doux Moiides. Paris, Soptenilx-r 1, 100.1. 



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