320 TRAVELS IN AFRICA, 
with the natives. " The ftink blinds me," is a frequent ex- 
preflion on coming into a place of fetid odour ; and it may be 
remarked, that the ordinary maxims of indigent are rarely ta 
be entirely difregarded. Whatever miafms however may ilTue 
from the canal, they cannot be equally difperfed over the city, 
as blindnefs is ; and the Franks, Greeks, and other ftrangers 
who refide neareft this depot of impurity, would be moft 
affected if that were the caufe. It may yet be one caufe. 
Another I take to be the fubtile dufl: above mentioned ; but the 
moft powerful, indifcreet expofure to the nod;urnal air and 
dews. The colle£tive influence of thefe is ftrengthened by 
the cloudlefs fplendour of a vertical fun, reflected from the 
fterile expanfe of fand, which offers no fombrous object on, 
which the eye may repofe itfelf. 
Thefe confiderations, it may be acknowleged, do not carry 
convi(5tion ; but too many local difeafes are yet unexplained, 
to leave any wonder if the caufe of thi& fliould yet remain, 
problematical. 
Plague^ 
All the improvements in the art of healing which modern 
Europe can boaft as its own, are the refult of more frequent 
experiment, and more patient and minute inveftigation, than 
exifted in the antient. 
To conjedture ingenioufly is a matter of fmall effort, and in 
treating of what is properly the objed of experiment, it is not 
only 
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