VELLOW FEVER PROPHYLAXIS IN NEW ORLEANS 15 



annual report (1902) to the Health Board in New Orleans, the Medical 

 Officer of Health states, " We assert our belief that excavations of 

 soil in summer are innocuous, and we take pride in having been the 

 first to permit work of improvement to continue uninterrupted and 

 unhampered during the summer months." I found in Central 

 America last summer (1905) that considerable prejudice existed 

 against excavations and dredging, and that outbreaks of Yellow Fever 

 were freely attributed to this cause. Needless to say, there is not 

 the slightest scientific foundation for the alarm, and the supposed 

 relationship is in reality an example of odd cases of coincidence. A 

 little enquiry will at once show that Yellow Fever appears in places 

 where no digging or dredging operations are in hand, and con- 

 versely, that excavating and dredging may take place every year in a 

 fKDrt liable to Yellow Fever without any Yellow Fever occurring. 

 There is no poison in the dredged or excavated material, and it can 

 neither infect human beings nor mosquitoes. The idea probably 

 arises from the fact of the well-known observation that malaria was 

 frequently observed to break out amongst those engaged in canal or 

 railway construction, or in other engineering enterprises on land, or 

 in harbour construction works. In some of these operations terrestrial 

 pools would probably be formed in large numbers and would become 

 the suitable breeding places of Anopheles, but not of the Stegomyia. 

 In any case the bringing together of a number of labourers in a 

 tropical town, living in huts crowded together without any screening 

 of the numerous water containers in order to protect them from 

 mosquitoes, would at once favour the spread of Yellow Fever were 

 it introduced. This has occurred, but is not due to the men turning 

 over the ground or dredging the harbour, but to the fact that they 

 were living under conditions which favoured the propagation of the 

 Yellow Fever mosquito. That this is so a comparison between the 

 monthly mortality on the Panama Canal zone to-day with that of 

 22 years ago under the old Canal Company is overwhelming proof. 



In October 1884, under the French Company, there were 21 

 deaths and 84 cases of yellow fever amongst 2,706 non-immunes, in 

 a total of 19,243 employees. In October 1905 amongst 4,000 non- 

 immunes, in a total of 22,000 employees, there was no death and only 

 one case. 



