270 Proceedings of Royal Society of Edinburgh, [sess. 
Geographical Distribution . — The distribution of malaria is very 
extensive, although the intensity of the malarial process varies in 
different regions. Commencing with Africa, we find that on the west 
coast malaria is very prevalent in the basins of the Senegal and 
Gambia, and on the Guinea coast from Sierra Leone to Cape Lopez, 
especially in the basins of the Niger and Gaboon, on the Ivory and 
Gold coasts, at Fernando Po, and St Thomas. It diminishes rapidly 
in intensity until lat. 18° S., where it disappears. On the East coast, 
the malarial region commences in the south at Delagoa Bay, and ex- 
tends northwards as far as 5° N. lat., including the islands of Zanzibar, 
Madagascar, Mauritius, Bourbon, and Seychelles. Areas of endemic 
malaria are also found in the lowlands of Abyssinia and in the 
Somali district, in the valley of the Nile, from Khartum to the 
Great Lakes, west of the Nile between Dongola and Khartum, and 
all over Tropical Central Africa, up to an altitude of 3000 feet. 
Egypt, Tripoli, Tunis, and Algiers are likewise affected. The 
malarial process is most intense upon the equatorial African coast- 
line until an altitude of 500 feet is reached, and it also extends in 
its gravest form for about 300 miles up the banks of the Zambesi, 
the Congo, and the Niger. 
Malaria is met with in Arabia, on the east coast of the Ked Sea, 
especially on the coast of Hedjaz, and in Yemen from Jisan south 
to Moccha. It is also found at Muscat, on the shores of the Persian 
Gulf and its islands, and in the valleys of the Euphrates and 
Tigris. It also exists in Syria, especially in the damp valleys 
of the Lebanon, in the valley of the Jordan and along the shores of 
the Levant; and this malarious area extends to Asia Minor, from 
Adana and Tarsus to the Dardanelles, including Smyrna. The 
disease extends all round the Caspian Sea, overspreads Persia, 
Beloochistan, and Afghanistan ; and is met with all over India, 
with the exception of places having a high altitude. Ceylon too 
and Burmah, Siam, Sumatra, Borneo, New Guinea, the Phillipine 
Islands, Japan, the Andaman Islands and Australia as far south as 
lat. 17°, are all affected. The disease also prevails in a severe form 
in the tropical and sub-tropical parts of China. 
In Europe we may commence by tracing malaria in the steppe 
lands of the Caspian. It follows the course of the Volga through 
Astrakan, includes the central Caucasian plain, and the countries 
