In December last he again called upon me and wished to know if more could not be done for him? He said he had continued to follow his business with the use of concave glasses, but saw with great difficulty. The vapour was employed thrice a week for about three weeks, when his vision was restored to its natural length. I saw him on the 21st of January, and he said he was perfectly well, and could follow his business with great pleasure to himself. CASE 10. _Amaurosis of the Left Eye, and Cataract of the Right._ GEORGE TROUSDALE, aged 37, horse-keeper, 37, William Street, Hampstead Road, says, that when he was 8 years of age, a shoemaker's awl was accidentally pushed through the right eyelid into the eye, which gave rise to an attack of severe inflammation in both eyes. When the inflammation subsided he found the vision of the right eye entirely gone. The left eye became dim in May last, and his sight was much disturbed by floating clouds passing before the eye. When he looked steadily at an object the vision almost vanished. He experienced great pain in the forehead and temple on the same side. He applied to an infirmary, where he remained as an out-patient for six weeks. He was salivated, cupped, and leeched. He was then told that the right eye was of no use, and they feared the vision of the left also was destroyed. He then went to an Ophthalmic Institution, where he remained as an out-patient for seven weeks. He was again salivated; a liquid was dropped into his eye regularly, and he was blistered, but no good resulted. He then went to a private oculist, under whose care he remained for six weeks. He again was salivated; but still the sight became more obscured, and the pains in his forehead and temple more acute. I saw him first in October; he was then suffering from severe pain in the forehead and temple. The left eye was so blind that he could not distinguish, even when placed close beside it, a large bookcase. He said he could scarcely guide himself in the street. The pupil was almost immoveable. There was a white cataract in the right eye, and a total want of vision. He has had the vapour of the prussic acid applied to both eyes almost daily since October. He can now, with the left eye, read ordinary-size print, and is free from all pain. Nearly the upper half of the cataract of the right eye is absorbed, and he is beginning to see with it. This case shows the power of the acid in not only producing absorption, but in the removal of amaurosis at the same time. Unless the capsule of the lens had been lacerated by the awl, I do not think that the acid could have had any power in causing absorption in a case of cataract which had existed for the long period of twenty-eight years. He is still under treatment. CASE 11. _Cataract._