DISTRIBUTION OF MALARIA 131 



our soldiers on the west coast of Africa have an 

 average of at least two attacks a year, and a consider- 

 able number of them die. There is no reason to 

 believe that the civil population of India or West 

 Africa is in any degree more exempt from the disease 

 than the military, but the statistics in the latter case 

 are more readily accessible. 



Malarial fever, when it does not kill, leaves great 

 weakness behind ; and all who have watched malaria 

 patients, or patients who are already recovering from 

 an attack, cannot fail to have noticed the listlessness 

 and want of interest in their surroundings and the 

 lack of inclination to work that they all show. Apart 

 from the mortality, the disease probably levies a 

 heavier tribute on the capacity of the officers and 

 officials who administer the British Empire than does 

 any other single agency. 



Before describing the organism which causes all 

 this misery a word or two must be said about the 

 distribution of the disease. Roughly speaking, malaria 

 is confined to a broad irregular belt running round 

 the world between the 4th isothermal line north of 

 the Equator and the i6th line south. It is, however, 

 said to occur occasionally outside these limits — for 

 instance, in Southern Greenland and at Irkutsk in 

 Siberia; but until recently the accurate diagnosis of 

 the disease has been difficult, and too much reliance 

 must not be placed on these statements. The chief 

 endemic foci of the disease are along the banks and 

 deltas of large rivers, on low coasts, and around 

 inland lakes and marshes. Malaria is common all 

 round the Mediterranean region : it was well known 

 to, and its symptoms were clearly noted by, the early 

 physicians since the time of Hippocrates. They even 

 recognized the difference between the mild spring 

 and summer attacks and the more pernicious effects 

 of the autumnal fever. In France there are several 



9—2 



