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XIX. Observations and Experiments on Vision. By William 
Charles Wells, M. B. F. R. S . 
Read July 4th, 1811. 
I. 1 was consulted, in the beginning of the year 1809, upon 
a disease of vision, which, as far as I know, has not hitherto 
been mentioned by any author. The subject of it was a gen- 
tleman about thirty-five years old, very tall, and inclining to 
be corpulent. About a month before I saw him, he had been 
attacked with a catarrh, and as this was leaving him, he was 
seized with a slight stupor, and a feeling of weight in his fore- 
head. He began at the same time to see less distinctly than 
formerly with his right eye, and to lose the power of moving 
its upper lid. The pupil of the same eye was now also ob- 
served to be much dilated. In a few days, the left eye became 
similarly affected with the right, but in a less degree. Such 
was the account of the case, which I received from the patient 
himself, and from the surgeon who attended him. The for- 
mer added, that previously to his present ailment his sight 
had always been so good, that he had never used glasses of 
any kind to improve it. On examining his eyes myself, I 
could not discover in them any other appearance of disease, 
than that their pupils, the right particularly, were much too 
large, and that their size was little affected by the quantity of 
light which passed through them. At first, I thought that 
their dilatation was occasioned by a defect of sensibility in the 
