. 1. 2. 2. OF SENSATION. 1 65 



or pungency, by the introduction of aqueous and mucilagi- 

 nous fluids, such as barley water, cream and water, sugar and 

 water, weak broths; to which may be added so much of some 

 vegetable essential oil, as may render them grateful to the sto- 

 mach, and thus promote their absorption; as by infusing parsley 

 or celery and turnips in the broth; or by balm, mint, or sage 

 teas. 



The following species of this genus only distinguish the situa- 

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

 cause of the sensitive irritated, or inflammatory fever, which at- 

 tends it. 



2. Ophthalmia interna. Inflammation of the eye is attended 

 with the production of new vessels, which spread over the tunica 

 adjunctiva, and over the cornea; these new vessels are easily 

 seen, as they lie on a white ground, and give ocular demonstra- 

 tion of their production in inflammation. When this inflamma- 

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

 which may be seen beneath the surface in the form of little ex- 

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

 an opaque scar. This scar, in some monihs or years, is liable to 

 wear away, and become transparent, without the assistance oi 

 any polishing powder, as of very finely levigated glass, as some 

 have recommended. But when the cornea is affected through 

 all its thickness, the return of its transparency becomes hopeless. 

 See Class I. 1. 3. 14. 



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

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

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

 occasions intolerable pain. This curious circumstance cannot 

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

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

 or retina is also rendered more exquisitely sensible to light, by 

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

 colours are in these cases sometimes painfully perceived even 

 in perfect darkness. This shews that the retina is excited into 

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

 these motions give great pain, like those of other inflamed parts, 

 as the muscles or membranes. And secondly, that the ideas 

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

 occasion : pain 3 when the extremity of the moving nerve is in- 

 flamed. 



M. M. Venesection. Cathartics. Diluents. Torpentia. 

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

 Cool airy room. Darkness. When the inflammation begins to 

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



