and distant Sight of different Persons. 37 



Sighted, and receiving assistance from the first number of a 

 concave glass, whereas the left eye derives no benefit from it. 

 This remarkable dilatation of the pupil of the right eye was first 

 noticed about twenty years ago, and a variety of remedies have 

 been employed at different times with a view to correct it; but 

 none of them have made any alteration. It should be mentioned, 

 that, in order to produce the contraction of the pupil, the ob- 

 ject looked at must be placed exactly nine inches from the 

 eye ; and if it be brought nearer, it has no more power to pro- 

 duce the contraction than if it were placed at a remoter dis- 

 tance. It should also be mentioned, that the continuance of 

 the contraction of the pupil depends, in some degree, on the 

 state of the lady's health; since, though its contraction never 

 remains long after the attention is withdrawn from a near ob- 

 ject, yet whenever she is debilitated by a temporary ailment, 

 the contraction is of much shorter duration than when her 

 health is entire.* 



Dr. Wells, in his ingenious paper, published in the Second 

 Part of the Transactions of the Royal Society for the year 



* Several instances have come under my notice, in which the pupil of one eye has 

 become dilated to a great degree, and has been incapable of contracting on an increase 

 of light, whilst the pupil of the other eye has remained of its natural size. In some 

 of these, the eye with the dilated pupil has been totally deprived of sight, the disorder 

 answering to that of a perfect amaurosis; but in others, the dilatation of the pupil ha$ 

 only occasioned an inability to distinguish minute objects. Reading has been accom- 

 plished with difficulty, and convex glasses have afforded very little assistance. Though 

 objects at a distance were seen with less inconvenience, than those that were near, these 

 also appeared to the affected eye much less distinct than to the other. Most of the 

 persons to whom I allude had been debilitated, by fatigue or anxiety, before the 

 imperfection was discovered in the sight ; and in some it had been preceded by affec- 

 tions of the stomach and alimentary canal. 



