DISTRIBUTION 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. Ina 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. 
“Tn Great Britain it used to flourish. The following extract from Graham’s 
© Social Life of Scotland in the Highteenth 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 
