M E D I C A. 
fcreafe of the moon, and repeat the fame courfc, 
Cairo, July i, 1751. 
Ophthalmia ^Egyptiorum. Difeafes of the Eyes. 
No Difeafes are more common in .Egypt than 
thofe that affe< 3 : the Eyes, efpecially in Cairo, where 
the greatelt part of the inhabitants are affii&ed 
with (Ophthalmia and Plorothalmia) fore and watry 
Eyes. More than one caufe may be given for this 
endemic diforder. The exceffive heat added to 
the incredible quantity of fine duft, which flies 
about the air of this dry country, is fufficient to 
make the difeafes of the Eye more frequent in 
Egypt, than any where elfo, and perhaps in 
iome places this alone may be the caufo. But i 
am fully penuaded, that it is not the only china- 
that occafions this diforder in the city of Cairo. 1 
have there cbferved one more remarkable. The 
inhabitants, efpecially thofe that live near the ca- 
nal, have under their houfes a fink or deep pit, 
that anfwers for a neceffary-houfe, for the recep- 
tion of all kinds of filth and excrements. From 
this fink there is a drain that leads into the canal 
which runs through the city, and is never opened 
but, in order to clear it our, once a year, and that 
at the time when the heat is moft violent, and the 
canal has foarcely any thing in it but the foetid 
nure left by the Nile : and to this filth and or- 
dure I afonbe the caufe of fore Eyes to the People 
ln Cairo, for whilfi: thefe putrid fu'oftances are fhut 
dp in the pit they infonfibly throw off fome noxi- 
ous particles, which become more perceptible when 
they are emitted into the canal, and unite their poi- 
fon with the circumambient air. To confirm my 
opinion, I need only ufethe argument, which induced 
v the, 
