"To resume, then, what I have said concerning the sense of vision and our several experiments, allow me once more to impress you with the idea that sight can never be exercised in a complete and perfect manner without a certain influence of the fifth pair of nerves; destroy that influence, and you destroy vision. This is all we know upon the matter; for up to the present moment we have been unable to determine how far this influence extends, or in what manner it is communicated." _Case of Amaurosis._ JOHN PLUNKETT, Mermaid Gardens, Hackney, formerly an attorney's clerk, visited me in May, 1837, and stated that he had been blind and obliged to be led about by his children for the last four years. For five years previously his sight had been gradually diminishing. He further stated that he was much troubled with floating images before his right eye, as well as with clouds resembling animals, strange goblins, and sometimes with flashes of lightning, vivid red, changing into light blue. One great peculiarity of this miserable man's case was, that when he threw back his head there appeared a stream of blood flowing from the top of the right eye to the centre, where it formed into a circular pool about the size of a split pea, but ultimately it became as large as a shilling. It often remained a considerable time, and then diminished gradually in red streaks. This was a matter of great alarm to him. He had been at several Ophthalmic Institutions for nine years previously to his visiting me. He has had electricity, tartarate of antimony, blisters, issues, stramonium, mercury (until it produced dysentery), and almost every kind of treatment that could be suggested, tried, but to no purpose. When I saw him the pupil was immoveable, and the eye dull in the anterior, and very obscure. The left eye was destroyed. He could not discern, in a bright light, the shadow of white paper when it was moved between him and the light. The compound embrocation of oil of cloves was used by rubbing it upon the forehead and temples daily, and in the space of twelve days he was able to discern objects and could touch them. In two months he could put his finger through a ring when held by another person. He continued occasionally under my care for about a year, during which time the embrocation was regularly used. He could walk alone, and the eye was generally useful, but he was not able to read with it. He could see objects at the distance of thirty feet. The last month he has visited me once or twice a week, for the purpose of having the prussic acid vapour applied to his eye, to ascertain if the sight could be restored sufficiently to enable him to follow his occupation as a clerk. In this case an advantage has been gained. The patient is now able to read a little, which, previously to the use of the prussic acid vapour, he was unable to do. _Amaurosis._