232 The Control of Mosquitoes 



under the direction of Colonel Gorgas, in February, 

 1901. 



Colonel Gorgas has treated this subject so 

 comprehensively in his final report to General 

 Leonard Wood that we quote from it : 



For over 200 years this disease had, at short inter- 

 vals, devastated the Atlantic and Gulf coasts of the 

 United States, causing great loss of life, and still 

 greater financial loss, due to the entire cessation of 

 commerce which occurred during the epidemic of 

 1878, which affected particularly the lower Mississippi 

 Valley, amounted to $100,000,000, and in years when 

 there was no epidemic, quarantines had to be kept up 

 against the infected regions around the Gulf of Mexico, 

 which stopped almost all travel and greatly interfered 

 with commerce. The United States had come to look 

 upon Havana as the particular point from which 

 infection was spread. Yellow fever had been con- 

 tinually present in this city since 1762. Every 

 month in every year during that time there have 

 been some cases. In all other localities of North 

 America where yellow fever occurred, it occurred 

 epidemically; that is, the locality was free from the 

 disease for a longer or shorter time. In places above 

 the frost line, winter always puts an end to the dis- 

 ease, and in localities in the tropics it always termi- 

 nates after a greater or lesser period of years from the 

 exhaustion of the non-immune material. 



Briefly stated, on February i, 1901, the date of 

 the commencement of anti-yellow fever work 



