202 Treatise on the Diseases of the Eye. 



" The peculiar circumstances in which the children were placed in 

 the Orphan Institution rendered them so susceptible of purulent 

 ophthalmia, that for nearly half a century it occurred very frequently 

 in the epidemic form, and produced the most distressing effects. In 

 February, 1821, there were 438 pupils more or less affected with 

 ophthalmia, and in September of the same year the following melan- 

 choly report was recorded — 



22 Children were totally blind. 



12 nearly so. 



58 with opacities and slight ulcerations. 



47 blind of one eye. 

 140 affected with purulent ophthalmia. 



279 



In 18 1 9 fresh infection was brought into the school by some children 

 who joined from the Upper Provinces, and two years after " the state 

 of the disorder was reported to be as bad now, if not worse, than it 

 ever was at any former period/' In the report of that period it is 

 stated " not one of the young children who have joined the school 

 during the last two months has escaped the contagion. 



Number in the School, Feb. 1821, Boys 270, Girls 354 : Total 

 624. Seven-tenths of 624 — 437*8 diseased." 



Fortunately the disease has never since then prevailed to 

 such an extent, and has of late years been uncommon. Dr. 

 Wise offers at considerable length some remarks on its pre- 

 vention for the future. 



We shall give the author's remarks on impaired vision, 

 Glaucoma, and Nyctalopia at length, as they are of consider- 

 able interest. 



Impaired vision : (pp. xiv — xviii.) 



" In tropical climates, the less sensitive and dark skin ; the black 

 eyebrows and eyelashes of the natives, have the effect of deadening 

 the glare of the powerful sun. The size of the pupil of the eye is dimi- 

 nished, by which means the quantity of light admitted into the retina 

 is proportioned to the intensity of the rays, and to the state of sensi- 

 bility of that delicate organ, the eye, as well as to the state of the 

 retina on which the image of visible objects is depicted. The degree 



