Dr. Wells’s Observations 
382 
want of the crystalline lens disables a person from having 
perfect vision at different distances ; for as Hanson was sixty 
three years old, it is highly probable, that the results of the 
experiments would have been exactly the same, if he had still 
possessed that part of his eye. 
III. Having discovered that my own eyes were unfit for the 
experiments, which I wished to be made with Belladonna, I 
instructed an ingenious young physician, Dr. Cutting, from 
the island of Barbadpes, and now residing there, in the man- 
ner elsewhere described by me,* of ascertaining his range of 
perfect vision by means of luminous points. This he found, 
in consequence, to begin, with respect to his left eye, at the 
distance of six inches, and not to terminate at the distance of 
eight feet, beyond which he could not see clearly the object, 
with which he had hitherto made his experiments, the image 
of the flame of a candle in the bulb of a small thermometer. 
The flame of a lamp, distant about sixty yards, gave a faint 
indication of its rays meeting before they fell upon the retina; 
the rays from a star had very evidently their focus a little 
before that membrane. He now applied the juice of Bella- 
donna to his left eye. Half an hour after, when his pupil was 
but little dilated, perfect vision commenced at the distance of 
seven inches ; in fifteen minutes more, it began at the distance 
of three feet and a half. When his pupil had acquired its 
greatest enlargement, the rays from the image of the flame 
of a candle, in the bulb of a small thermometer at the distance 
of eight feet, could not be prevented from converging to a 
point behind the retina. The rays from lamps still more dis- 
tant, and from stars, had their focuses at the same time on 
* Essay on Single Vision, &c. p. 116. 
