EXAMPLES OF MOSQUITO EXTERMINATIVE MEASURES. 101 



of swamps, covering of drinking-water reservoirs, and the use of 

 petroleum. 



In the course of this work and that which followed, with the under- 

 standing that Veracruz is the oldest and most permanent focus of 

 endemia of the Mexican Republic, and that all the epidemics had 

 found their origin in that place, the principal attention of the superior 

 board of health was devoted to that city. The town was divided into 

 four districts, each of which was placed under the charge of an expe- 

 rienced ph3^sician, and each of these had first-class sanitary agents. 

 Subordinate to these, other second-class agents were appointed, and 

 a certain number of laborers were added. As a result of this effective 

 organization, Carroll, writing his chapter on yellow fever for Osier's 

 Modern Medicine, at the close of 1906, was able to make the following 

 statement : 



In Mexico yellow fever has been eradicated from its endemic focus at Veracruz 

 through the able efforts of Eduardo Liceaga, the president of the superior board of 

 health, whose complete grasp of the problem and whose enlightened and energetic 

 action has added support to the mosquito doctrine, and would have controlled the 

 disease absolutely if the same means of enforcement were available in Mexico as in 

 Cuba in 1901. 



The later developments of the work in the Mexican Republic under 

 Doctor Liceaga's leadership have been remarkable. In the American 

 Journal of Public Hygiene, new series. Volume VI, No. 1 (February, 

 1910), is published Doctor Liceaga's Annual Report on Yellow Fever 

 in the Mexican Republic, from August 16, 1908, to date, a paper read 

 before the American Public Health Association, at Richmond, Va., 

 October, 1909. The following paragraphs concluding this report will 

 give an idea of the excellent results which have followed the work of 

 the sanitary officials in Mexico : 



The campaign against yellow fever, which commenced in the Mexican Republic 

 in the year 1903, has continued uninterrupted up to this date, without even suspending 

 it during the winter months as is done in other countries; that the war on the mos- 

 quitoes is so efficacious that there are none left in Veracruz, and, consequently, there 

 are no stegomyias, as demonstrated by the reports rendered by the physician of the 

 Public Health and Marine-Hospital Service of the United States, who is resident in 

 that port. 



The cases which have been observed in Merida and surrounding villages arise from 

 the existence in that city of over thirty thousand water tanks which could not be so 

 easily and securely watched as those of Veracruz. 



In the entire section which was formerly devastated by yellow fever we continue 

 to canalize the deposits of standing water and to fill up the hollows, as well as to 

 spread oil on all those ponds which cannot be otherwise filled in or covered. 



We continue to fumigate the dwelling houses, workshops, schools, etc., in which 

 we have encountered either cases of yellow fever or any suspected cases. 



We continue the surveillance over the passengers who travel by rail in any part of 

 the region which formerly suffered from yellow fever, and this service is especially 

 active along the line of the Tehuantepec Railroad. 



In the ports of Coatzacoalcos, on the Gulf coast, and Salina Cruz, on the Pacific, it 

 is nearly four years since a single case of yellow fever was observed. 



