Yellow Fever and Other Diseases 113 



virus a remarkable resistance, thus concealing its 

 character and preventing the taking of isolative 

 measures, as well as the presence of such fevers 

 among the immunes by habitat. The physicians of 

 New Orleans used to believe that, as although Cre- 

 ole children had what was called the " prevailing 

 fever," yet did not have characteristic yellow fever, 

 therefore the two fevers were not the same. This 

 old belief in the immunity of native-born children 

 was exploded by the Yellow Fever Commission of 

 1897. Since then we have known that the almost 

 complete exemption enjoyed by children in prac- 

 tically endemic areas during years gone by was not 

 due to inherent vital resistance, but rather to im- 

 munity acquired by an attack of the disease in in- 

 fancy, when the resistance is high and the disease 

 therefore mild and thus unrecognised. 



Can Yellow Fever be Transmitted through the 

 Egg? — If, indeed, yellow fever is due to a protozoan, 

 it is quite within the range of possibility that the 

 organism might pass into the eggs of the infected 

 mosquito and thus infect the second generation of 

 insects without their ever coming into contact with 

 a yellow-fever patient, just as the Texas cattle fever 

 is transmitted from the tick to its eggs. Though the 

 experiments along this line have, for the most part, 

 been negative in result, still they have not been alto- 

 gether so. It is true that Reed and his associates 

 in Havana found that the bites of fourteen mosqui- 

 toes, hatched from the ova of an S. calopus which had 

 already shown itself capable of conveying the disease, 



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