Report of the Departmental Committee on the Causes and Prevention of Blindness: Conclusion and Summary of Recommendations.

all the distributing electric light stations, it has not yet been found practicable to make a lamp which will stand the strain. Hence we have to be content with somewhat indifferent carbon filament lamps. Before the war many operation lamps such as Jessop's were fitted with a Nernst filament; as this is no longer obtainable the lamp is rendered useless. A very excellent substitute for the Nernst is the Ediswan Pointolight which has been fitted in some instances into the existing tubes by Messrs. Hamblin. This lamp has the disadvantage that it requires a resistance in the circuit, and although suitable for an operating theatre, cannot be carried into wards. Further, it is difficult to bring the filament sufficiently close to the focussing system of lenses to get an even illumination. To obviate this difficulty there has been produced quite recently a spiral metal filament gas-filled lamp, the filament of which is brought close -against the glass on one side for projection. It is manufactured in all voltages, and does not require any resistance in the circuit, and can be used in either an operating lamp or in the lamp described below for use in the wards. It is manufactured by the British General Electric Co., and by Siemen Bros. A very excellent ward lamp designed and produced by Messrs. Rayner and Co., in consultation with ophthalmic surgeons and members of the Illuminating Engineering Society. It is readily portable, gives a definite spot of light of even brilliancy, a-nd has discs of ground and Chance's daylight glass to place before it, if desired. The same firm has produced an excellent shadowless lamp for the general lighting of the operating field, which consists of three separate lens systems similar to the hand-lamp, deriving its source of light from a half-watt bulb.