BANISHING THE PLAGUES 



in 1905 was 49.94; in 1912 it was 20.49. As regards 

 the former scourges of the region, Colonel Gorgas 

 reports as follows: One case of yellow fever on a 

 ship from Guayaquil, Ecuador, was isolated in Santo 

 Tomas Hospital and died there on July 14th. With 

 this exception, no case of yellow fever, plague or 

 smallpox occured on the Isthmus during the year." 



It should be understood, however, that the work 

 of making the Canal Zone permanently salubrious 

 is by no means completed. The monthly report for 

 February, 1913, shows that the task of making ditches 

 to drain areas where the mosquitoes breed is still 

 under way, and that there are regions where the dead- 

 ly Anopheles, the carrier of malaria germs, still exists 

 in sufficient numbers to be a menace. The report tells 

 of tests with mosquitoes stained for indemnification, 

 in which the marked individuals were found at a dis- 

 tance of 6,000 feet, or considerably over a mile, from 

 where they were liberated. 



This fact will be of interest to the local health au- 

 thorities of many regions of the temperate zone, inas- 

 much as there has been a prevailing opinion that a 

 mosquito can travel but a short distance from its 

 breeding haunts. It becomes evident that local health 

 boards who wish to protect their villages from inva- 

 sion by the malaria-carrying mosquito must pay 

 attention to ponds or other reservoirs of stagnant 

 water for a radius of more than a mile. 



A long time will doubtless elapse before such con- 

 ditions as Colonel Gorgas has brought about in the 

 Canal Zone will obtain widely in tropical regions. 

 Nevertheless, the object lesson has already inspired 



253 



