CLASS II. i. 4. i. OF SENSATION. 219 



f ymptom of fcrofula, when it recurs frequently in young per- 

 fons; but is probably only a concomitant of that difeafe, as a 

 fymptom of general debility ; ramifications of new red veffels, 

 and of enlarged old ones, are fpread over the white part of the 

 eye ; and it is attended with lefs heat, lefs pain, and lefs intoler- 

 ance of light than the ophthalmia interna, defcribed in Clafs II. 

 i. 2. 2. It occurs in thofe of feeble circulation, efpecially chil- 

 dren of a fcrofulous tendency, and feems to arife from a previ- 

 ous torpor of the veflels of the tunica albuginea from their being 

 expofed to cold air ; and from this torpor being more liable to 

 occur in habits, which are naturally inirritable ; and therefore 

 more readily fall into quiefcence by a fmaller deduction of the 

 ftimulus of heat, than would affect ftronger or more irritable 

 habits ; the confequence of this torpor is increafed action, which 

 produces pain in the eye, and that induces inflammation by the 

 acquifition of the additional fenforial power of fenfation. 



Ophthalmia lymphatica is a kind of anafarca of the tunica adna- 

 ta ; in this the veflels over the fclerotica, or white part of the 

 eye, rife confiderably above the cornea, which they furround, are 

 lefs red than in the ophthalmia fuperficialis, and appear to be 

 f welled by an accumulation of lymph rather than of blood ; it 

 is probably owing to the temporary obilruclion of a branch of 

 the lymphatic fyftem. 



M. M. If the pain be great, yenefeftion by leeches on the 

 temple, or cutting the temporal artery, and one purge with three 

 or four grains of calomel ihould -be premifed. Then the Peru- 

 vian bark twice a day. Opium from a quarter to half a grain 

 twice a day, for fome weeks. Bathe the eye frequently with 

 cold water alone, or with cold water to a pint of which is added 

 half an ounce of fait. White vitriol, fix grains difTolved in one 

 ounce of water ; a drop or two to be put between the eyelids 

 twice a day. Take very fmall electric fparks from the eyes eve- 

 ry day for a fortnight. Bathe the whole head with fait and wa- 

 ter made warm, every night, for fome months. Send fuch chil- 

 dren to a fchool near the fea, for the convenience of fea- bathing, 

 for many months, annually ; fuch fchools are to be found in or 

 near Liverpool. 



When a child is afflicted with an inflamed eye of this kind, 

 he fhould always fit with his back to the window or candle ; 

 but it is generally not neceflary to cover it, or if the uneafy fen- 

 fation of light makes this proper, the cover fhould (land off from 

 the eye, fo as not much to exclude the cool air from it. As 

 covering an eye unneceflarily is liable to make that eye weaker 

 than the other, from its not being fufficiently ufed, and thenje 

 to produce a fquinrjng forever afterwards. 



Never thelefs* 



