282 Proceedings of Royal Society of Edinburgh. [sess. 
Ocean have remained unaffected "by the disease. So too has the 
whole of Africa, with the exception of a strip of coast-land 
commencing at Delagoa Bay and running all round the eastern and 
northern coasts of the Continent as far as lat. 14° N. The islands 
of St Helena and Ascension have also escaped. In South America, 
Terra del Fuego, Patagonia, Chili, the higher slopes of the Andes 
and the Falkland Islands have been hitherto exempt. In North 
America, the whole of the country north of 50° 1ST. lat. has remained 
free from cholera, as well as the highest slopes of the Rocky 
Mountains and the Bermudas. Greenland and Iceland have not 
been visited by the disease. 
In Europe, we find that the Faroe Islands, the Hebrides, the 
Shetlands and Orkneys, Lapland, the Russian territory north of 
the 64th parallel, Switzerland, and the northern part of Scotland 
have escaped. 
In Asia, the northern districts of Siberia and Kamtschatka have 
remained free, as also probably Mongolia and Manchuria. We see 
from these exceptions, what an immense area of the earth’s surface 
has been visited from time to time by the terrible scourge of cholera. 
It must be remembered, however, that, although the area of distribu- 
tion of cholera has been so vast, yet certain isolated districts in 
the various countries visited by it have remained unaffected. For 
instance, some mountainous districts in the south-west of France, 
the south-west of Germany, notably Baden and Wiirtemburg, and 
the greater part of Greece. 
Even in India itself there are places where its ravages are 
unknown ; for instance, it has not attacked the hilly regions of 
Bengal, but the reason for this is apparently to be found in the 
fact that the hill men have little or no communication with indi- 
viduals from the affected area. Should they descend from their 
mountains, or have any communication with the inhabitants of the 
plain, they suffer from the disease very severely. 
With regard to the home of cholera, we must define it as 
situated in the delta and valley of the Ganges, from which point it 
receives an impulse which enables it at times to become pandemic in 
character. There can be no doubt that cholera existed long before 
1817 ; of its previous epidemic spread no very certain informa- 
tion can be given, but that it overspread India and the adjacent 
