Importance of the Campaign 315 



has been about 40,000, practically all of whom are 

 non-immune. Their families residing on the Zone 

 and in Panama and Colon would add approxi- 

 mately as many more. If the yellow fever rate 

 of the French company's employees is used as a 

 basis for estimating the probable yellow fever mor- 

 tality among the canal employees between 1905 

 and 191 5 a mortality of about 1400 per annum 

 among the employees would not err on the side of 

 exaggeration. To this should be added at least 

 an equal number for the employees' families, were 

 their families there. At this rate, during the ten 

 years estimated for the completion of the canal, 

 mortality from yellow fever would reach the 

 frightful total of 14,000 employees, — 300 deaths 

 for each mile of the canal. Even this estimate is 

 based on the assumption that yellow fever in- 

 creases in direct ratio with the increase of non- 

 immune population, and that the number of 

 cases of yellow fever progresses along a definite 

 level, while in fact, the curve of yellow fever 

 ascends much more rapidly than the curve of non- 

 immune population; as knowledge of the mode of 

 the transmission of yellow fever would premise. 



It is impossible to estimate even approximately 

 the probable mortality from yellow fever had its 

 devastation been left unchecked. 



