274 



EYE-SIGHT. 



FALKLAND ISLANDS. 



properly adjusted lens of glass in front of the 

 eye. This, of course, is absolutely without the 

 power of accommodation, and different glasses 

 have to be used for seeing at different dis- 

 tances. Professor Helmholtz adopts the con- 

 clusion that tho perfection of tho eye depends 

 not upon the excellence of its construction as 

 an optical instrument, but upon the manner in 

 which it is used. The chromatic aberration 

 of its humors, the astigmatism of its irregular 

 contours, the blind-gaps of its nerve-screen, 

 the imperfect transparency of its refractive 

 media, the interposition of blood-vessels in 

 front of the retinal membrane, the narrow limi- 

 tation of the area of sharp definition, and the 

 prevalent blurring of the lateral parts of the 

 field, are all conditions that must be classed as 

 optical imperfections. Yet every one of these 

 imperfections is so counteracted and neutral- 

 ized in the use of the organ under the plan of 

 the employment of two eyes, and under the 

 expedient of the rapid transference of the at- 

 tention to different parts of the image, that it 

 is actually unrecognized as a defect, and undis- 

 covered until the most refined powers of scien- 

 tific investigation have been brought to bear 

 for its detection. 



There are many injuries to which the eye is 

 subject, and many conditions having an impor- 

 tant bearing on the preservation of good eye- 

 sight, besides those mentioned in connection 

 with structural or induced defects of form. It 

 is Mr. Carter's belief that a very large propor- 

 tion of what is generally regarded as congeni^ 

 tal blindness is really caused after birth by 

 ignorant or careless treatment. He puts the 

 proportion as high as ninety-nine cases in one 

 hundred. The eyes of new-born infants are 

 doubtless extremely sensitive to the effects of 

 light and temperature, and are imperfectly 

 shielded by nature. " From the imperfect de- 

 velopment of the bones of the infant skull," 

 says Mr. Carter, " the eyes are placed, so to 

 speak, on the surface, instead of being in hol- 

 lows; the eyebrows and eyelashes are short, 

 thin, and pale; the eyelids are almost trans- 

 parent, and the irides are imperfectly furnished 



with opaque pigment. In the first weeks of 

 life, moreover, infants are unable to shelter 

 themselves from dazzling light by changing 

 the position of the head." Protection from 

 too strong light and from sudden or violent 

 changes either of light or temperature, proper 

 attention to cleanliness and ventilation, and 

 the intelligent treatment of purulent ophthal- 

 mia when it shows itself, would in his opinion 

 prevent a very large proportion of the cuses of 

 blindness generally believed to be congenital. 



Artificial illumination is more trying to the 

 eyes than daylight, but, when its use is neces- 

 sary, the risk of injury may be reduced to a 

 minimum. There is little choice between oil- 

 and gas-light of a similar illuminating power. 

 Mr. Carter remarks, "The best illumination 

 for all purposes of close work is that of a 

 Silber Argand burner, it matters not whether 

 for gas or oil, placed to the left front of the 

 worker, a little above the level of the eyes, 

 fitted with a shade to reflect light upon the 

 table and to intercept it above, and with the 

 addition of an alum screen when the heat 

 is objectionable." When several lights are 

 used, they should be grouped together, as all 

 cross-lights are distressing to the eye. Mr. 

 Carter recommends that the least exacting 

 kind of work should be done in the evening or 

 at night; and, for literary men, reading and 

 study by day and writing at night is the best 

 arrangement. Reading in cars or other mov- 

 ing conveyances, and the close use of the eyes 

 by dim or unsteady light, are universally con- 

 demned. Smoke is injurious to the eyes and 

 eyelids, but, aside from its external irritating 

 effect, Mr. Carter does not agree with some 

 older writers in the opinion that tobacco- 

 smoking produces any material injury to the 

 eyes or optic nerves. According to the same 

 authority, colored glasses should not be used 

 except under competent surgical advice. But 

 where protection is desired for healthy eyes 

 from the glare of a strong light, or from reflec- 

 tion on snow or water, pale cobalt-blue or 

 neutral gray is to be preferred to green or 

 very dark glasses. 



FALKLAND ISLANDS. These islands 

 form a group in the South Atlantic Ocean, 

 about two hundred and fifty miles northeast of 

 Tierra del Fuego. The number of islands is 

 about two hundred, but only two of them are 

 of any considerable size. Their whole super- 

 ficies is reckoned at 5,000,000 acres. A few 

 years ago penguins and sea-lions chiefly occu- 

 pied their shores; but of late the English 

 Government has encouraged emigration to 

 them, and now numberless sheep fatten on 

 their grass. These yield to their owners such 

 an abundance of wool that it has become an 

 article of Exportation growing yearly in impor- 



tance. No other English colony has relatively 

 made such progress during the last ten years. 

 The population has doubled and the produc- 

 tion has quadrupled. According to the state- 

 ments of the English colonial office, the imports, 

 which in 1867 amounted to 20,590, had in 

 1878 increased to 35,040. The exports, 

 amounting in 1867 to 15,460, had increased in 

 1878 to 55,470. The population in 1867 was 

 705, and in 1878 it had increased to 1,394. 

 The value of the exports relatively to the num- 

 ber of the inhabitants is 40 to each ; while in 

 Australia it is 19 to each, and in the United 

 States it is 4. The balance of trade in favor 



