Class II. i. 2. 2. OF SENSATION. 165 



«y, or pungency, by the introduction of aqueous and mucilagin- 

 ous fluids, fuch as barley water, cream and water, fugar and 

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

 vegetable eflenrial oil, as may render them grateful to the ftom- 

 ach, and thus promote their abforption ; as by infufmg pariley 

 or cellery and turnips in the broth •, or by balm, mint, or fagc 

 teas. 



The following fpecies of this genus only diliinguifh the fitua- 

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

 caufe of the fenhtive 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 

 adjunct iva, and over the cornea ; thefe new veflels are eafily 

 feen, as they lie on a white ground, and 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 aiTiitance of 

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

 have recommended. But when the cornea is affected through 

 all its thicknefs, the return of its tranfparency becomes hopeieis. 

 See Oafs I. 1. 3. 14. 



In 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 lead light admitted to the eye 

 cccafions intolerable pain. This curious circumflance cannot 

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

 cornea. ; it therefore (hews, that the extremity of the optic nerve 

 cr retina is alfo rendered more exquifltely fenfible to light, by 

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

 colours are in thefe cafes fometimes painfully perceived even 

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

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

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

 as the mufcles, or membranes. And fecondly, that the ideas 

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

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

 earned. 



M. M. Venefectlon. Cathartics. Diluents. Torpentia. 

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

 Cool airy room. Darknefs. When the inflammation begins to 

 decline, white vitriol gr. vi. in an ounce of water is more eaiea- 



cious 



