CLASS II. i.2. 2. OF SENSATION. 165 



rv, or pungency, by the introduction of aqueous and mucilagin- 



:!uids, iuch as barley water, cream and water, fugar and 



water, weak broths ; to which may be added fo much of fome 



vegetable eflential oil, as may render them grateful to the (tom- 



and thus promote their abforption ; as by infufing parfley 



;ilery and turnips in the broth ; or by balm, mint, or fage 



teas. 



The following fpecies of this genus only diftinguifli the fitua- 

 tion of the part previoufly inflamed, and which is the remote 

 caufe of the fenutive irritated, or inflammatory fever, which at- 

 tends it. 



2. Ophthalmia interna. Inflammation of the eye is attended 

 with the production of new veflels, which fpread over the tunica 

 adjunctiva, and over the cornea ; thefe new veffels are eafily 

 feen,as they lie on a white ground, an.d give ocular demonftra- 

 tion of their production in inflammation. When this inflamma- 

 tion of the cornea fuppurates, it is liable to leave little ulcers, 

 which may be feen beneath the furface in the form of little ex- 

 cavations ; and as thefe heal, they are liable to be covered with 

 an opaque fear. This fear, in fome months or years, is liable to 

 wear away, and become tranfparent, without the afliilance of 

 any polifhing powder, as of very finely levigated glafs, as fome 

 have recommended. But when the cornea is affected through 

 all its thkknefs, the return of its tranfparency becomes hopelefs. 

 See Clafs I. i. 3. 14. 



la violent degrees of ophthalmy the internal parts, as the reti- 

 na, optic artery, iris, ciliary procefs, become inflamed, as well 

 as the external ones ; hence the leaft light admitted to the eye 

 occafions intolerable pain. This curious circumftance cannot 

 be owing to the action of light on the inflamed veflels of the 

 cornea ; it therefore mews, that the extremity of the optic nerve 

 or retina is alfo rendered more exquifitely fenfible to light, by 

 partaking of the inflammation ; arid I have been told, that red 

 colours are in thefe cafes fometimes painfully perceived even 

 in perfedt darknefs. This (hews that the retina is excited into 

 motion by the ftimulus of light ; and that, when it is inflamed, 

 thefe motions give great pain, like thofe of other inflamed parts, 

 3S the mufcles, or membranes. And fecondly, that the ideas 

 of colours confiil in the motions of the retina ; which ideas 

 occafion pain, when the extremity of the moving nerve is in- 

 flamed. 



M. M. Venefe&ion. Cathartics. Diluents. Torpenfia. 

 Frequently moiften the eye with cold water by means of a rag. 

 Cool airy room. Darknefs. When the inflammation begins to 

 4ecline, white vitriol gr. vi. in an ounce of water is more effica- 

 cious 



