DISTEIBUTION OF MALARIA 233 



Such localities or such regions are either those into which malaria has never 

 been introduced or those in which it has been absolutely stamped out. Also the 

 species of Anopheles present may be such as do not act as efficient hosts for 

 the malarial parasites, or, as has been already indicated on a previous page, the 

 proper species of Anopheles and of malarial organisms may not coincide. A 

 general consideration of the geographic distribution of the disease is given by 

 Shipley as follows : 



" 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 

 16th 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 prominent malarial districts : the 

 valley of the Loire and its tributary the Indre, and the valley of the Rhone; 

 also the sea-coast stretching from the mouth of the Loire to the Pyrenees, and 

 again the Mediterranean sea-board. It occurs in Switzerland, and is found in 

 Germany along the Baltic coasts, and on the banks of the Rhine, the Elbe, and 

 other rivers, and in many other parts. Scarcely a province in Holland is quite 

 free from it, and it is found in Belgium and around Lake Wener, in Sweden. 

 It extends along the Lower Danube and around the Black Sea, and spreads 

 across Russia, being especially prevalent along the course of the Volga and 

 around the Caspian. From Europe it spreads over Asia Minor, and affects all 

 Southern Asia as far as the East Indies, but in Japan it is curiously rare. It 

 is also infrequent in Australia — where it is confined to the northern half of the 

 continent — and in many of the Pacific Islands ; and it is unknown in the Sand- 

 wich Islands, New Zealand, Tasmania, and Samoa. In America it is more 

 common, and of a more severe type on the Atlantic sea-board than on the Pacific ; 

 in the last hundred years its northern limit is said to have retreated in the 

 centre of the continent, though some observers think it is creeping further north 

 in the Eastern States. In a mild form it is known around the Great Lakes, and 

 in Canada and in New England ; but it reaches a high degree of intensity in the 

 Southern States, Mexico, Cuba, and Central America, where it probably played 

 a greater part in ruining the projected Panama Canal than all the corrupt 

 financing of the speculators in Paris. It extends throughout the warmer parts 

 of South America, and is known in a virulent form all over Africa except the 

 extreme south. 



" In Great Britain it used to flourish. The following extract from Graham's 

 ' Social Life of Scotland in the Eighteenth Century ' shows what a part it played 

 in the life of the Scottish peasant : 



" ' The one ailment to which they were most liable, and in which dirt had no 

 share, was ague. This was due to the undrained land, which retained wet like 

 a sponge, and was full of swamps and bogs and morasses in which " green grew 

 the rushes." Terribly prevalent and harassing this malady proved to the rural 

 classes, for every year a vast proportion of the people were prostrated by it, so 

 that it was often extremely difficult to get the necessary work of the fields per- 

 formed in many districts. In localities like the Carse of Gowrie, which in those 



