. The electro-magnet and its employment in ophthalmic surgery : with special reference to the detection and removal of fragments of steel or iron from the interior of the eye. ity of cases. Gruening of New York, after various experiments,devised a magnet formed of a number of cylindersjoined together and united with a cap at each end, andat one extremity he inserted a needle fifty-two milli- metres long, one millimetre wide, and 0*3 thick. Thisinstrument will support from the point a key weighingtwenty-eight grammes (nearly one ounce). The attrac-tive force of this magnet seems hardly greater
. The electro-magnet and its employment in ophthalmic surgery : with special reference to the detection and removal of fragments of steel or iron from the interior of the eye. ity of cases. Gruening of New York, after various experiments,devised a magnet formed of a number of cylindersjoined together and united with a cap at each end, andat one extremity he inserted a needle fifty-two milli- metres long, one millimetre wide, and 0*3 thick. Thisinstrument will support from the point a key weighingtwenty-eight grammes (nearly one ounce). The attrac-tive force of this magnet seems hardly greater than thesimple bar-magnet used unsuccessfully in Case No. 18,and is, as will be noticed further on, very little com-pared to that of an electro-magnet; for the best devisedsimple-bar or -other magnet is far inferior to a pro-perly constructed electro-magnet, which readily fulfilsthe requirements necessary for our purpose. Experience has not only confirmed the opinionformed as to the efficiency of the electro-magnetdevised by the author and described in the ( BritishMedical Journal in 1881, as before mentioned, but thesuccess attained in the fiery ordeal of practice has. [Half Actual Size.] demonstrated its value. Several ophthalmic surgeonshave adopted it, and in other instruments its principlehas been incorporated. As at present used it is some-what less in size than the original instrument, but itsefficiency has been maintained. Briefly described, theelectro-magnet * consists of a core of soft iron aroundwhich core is placed the coil of insulated copper-wire, * Made by Messrs. Cubley and Preston, High Street, Sheffield. 8 and this, again, is enclosed in an ebonite case. Toone end of the instrument are attached the screws toreceive the battery connections. At the other extre-mity the core of the magnet projects just beyond theebonite jacket and is tapped, and into it screws aneedle, which fits closely on the end of the instrumentby a projecting* cap. By this means it is possib
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Keywords: ., boo, bookcentury1800, bookdecade1880, booksubjecteye, bookyear1883
