PREFACE TO THE THIRD EDITION 



Since writing the prefaces to the first and second 

 editions, I have had the advantage this year of an 

 extended tour of investigation in West Africa in con- 

 nection with an outbreak of yellow fever. 



What has been written in this volume in connec- 

 tion with yellow fever in Central and South America 

 and in the West Indies holds equally good for West 

 Africa. If West Africa will grapple with the problem 

 in the same business-like way in which the West 

 Indies, Central and South America have done, there 

 is no doubt that yellow fever will be banished from 

 the Coast ; and that in consequence one at least of 

 the causes of mortality in that hitherto unsavoury 

 part of the world will disappear. 



In this third edition 1 have added a few photo- 

 graphs illustrating the progress of the antimosquito 

 campaign in Africa. 



October 24, 1910. 

 Ti 



