328 ' OBSERVATIONS AND EXPERIMENT! ON' YISION. 



near objects longcr-sighted. The power, consequently, in 

 tliis gentleman, to adapt the eye to difFerent distances, is 

 either totally lost or much diminished ; but the point, or 

 small space to which his perfect vision is now confined, in, 

 stead of being the most remote to which he could formerly 

 accommodate his eyes, as is commonly the case with the or- 

 dinarily sighted when they are becoming old, is now placed 

 between the tvvo extremes of his former range of accurate 

 Similar in- vision. The eyes of the other short-sighted person, a phy- 

 stance. sician of considerable learning, whose vision has been alter- 



ed by age, have been affected in a similar manner, but not 

 in so great a degree. 

 Range of per- As the only change, which had occurred from age in the 

 ^ k ^6d°b th S'S^*^ °^ ^^^^ ^^ ^y acquaintance as were considerably 

 w^ysbyage. myopic, was a lessening, on both sides, of their range of 

 perfect vision, I conceived, that this might be the ordinary 

 procedure of nature in such cases, and that it might be imi- 

 tated, in a young short-sighted person, by the application 

 Experiments of belladonna to his eyes. I have hitherto not been able to 

 "*^^*" ^^^'^^"""* obtahi permission to make the experiment on any young 

 sighted person, person, who is very short-sighted. Two gentlemen, how- 

 ever, who are somewhat short-sighted, have readily sub- 

 mitted to it; one of them, Mr. Blundell, a diligent and in- 

 genious student of medicine; the other, Mr, Patrick, a well 

 - educated young surgeon in London. The first experiment 

 was on Mr. Blundell, and the apparent result was, that the 

 range of his accurate vision was considerably diminished at 

 both ends, but not annihilated. Mr. Blundell, however, 

 afterward informed me, that he repeated the experiment 

 with more care in the country, and found, that in one eye 

 the nearest point of perfect vision was moved forward about 

 two thirds of the whole range, and in the other about one 

 third ; but that, with respect to both eyes, the most remote 

 points of the ranges were unchanged. He added, that while 

 one eye was under the influence of the belladonna, the other 

 became shorter.sighted than it had been before; but the 

 difference was not so great, as to induce me to place entire 

 confidence in the justness of his observation. I think it 

 right to mention here, that from mistake I applied only two 

 thirds of the ordinary quantity of belladonna tu his eye, in 



the 



