EGYPT, AND SYRIA. 317 
Something more plaufible indeed offers itfelf as to the inju- 
rious operation of an external caufe. Nothing can be more 
fubtle than the dull into which the vegetable foil of Egypt re- 
folves itfelf when it becomes dry. This, during a certain portion 
of the year, is in a manner fufpended in the air, from a caufe 
which exifts in few other countries, I mean the want of rain. 
It alfo contains a large portion of nitre, which is copioufly pro- 
duced in Egypt. This circumftance, however, is common to 
many other places. This light duft, doubtlefs of a very irritat- 
ing quality, not only floats in the ftreets, but pervades the apart- 
ments of every dwelling, infmuating itfelf into the moft artfully 
conftru£ted inclofures : l)y it therefore the eyes may and muft 
be in fome degree affeded. But Nature has not ordained that a 
part fo much expofed fliould be deftitute of its appropriate pro- 
tedlion. The fecretions of the lachrymal glands are, in general, 
abundantly fufficient to counteract the injury fuftained by the 
adlion of corrofive or irritating fubftances on the external fabric 
of the eye, being always produced exa6tly in proportion to the 
circumflances that demand them, as daily experience confirms : 
yet it cannot be denied, that the continually repeated operation 
of an offending caufe, when no remedy is applied, may be 
more than commenfurate with the efforts of Nature to reftore 
herfelf. 
Such is precifely the condition of the Kahirines. The ac- 
commodating the quaUty of diet to the fymptoms of derange- 
ment in the economy is a precaution unknown to them : and 
of their remedies, many are fo prepared, or fo adminiflered, as 
to augment rather than to annihilate dlfeafe. No idea offers 
itfelf 
