1. _Operations for the removal of the lens out of the way without its removal from the eye._--These used to be extensively practised under the name couching, and are of two kinds,--_Depression_, where the lens is simply pushed down from its place by a needle; _Reclination_, in which it is shoved backwards (turning on its transverse axis) as well as downwards. These are relics of old surgery, and very rarely practised by any oculists of eminence, as, though easy to perform, and with very flattering immediate results, the risks of chronic inflammation of the whole globe and injury to the retina are very great. 2. _For solution._--THE NEEDLE OPERATION.--Suitable (among other cases) especially in congenital cataracts in infants, and in cases of diabetic cataract. The principle of this operation is that the lens, once the capsule is freely opened in front and the aqueous humour admitted, is found rapidly to become absorbed and disappear, if the cataract has been a soft one. _Operation._--A needle with a lance-shaped head is to be used. It should be so made that the rounded shaft of the needle is just large enough to play freely in the wound made by the broader point, and yet not so small as to allow the aqueous humour to escape rapidly. The pupil has been dilated, the patient is lying on his back, and the globe is fixed by forceps attached to the conjunctiva of the inner side of the eye, and held by an assistant. The surgeon then enters the needle close to the sclerotic margin of the cornea, carries it fairly on in the anterior chamber, till the centre of the pupil is reached. He then, by bringing forward the handle, projects the point backwards against the anterior capsule, which he freely lacerates with the point and edge in several directions. In infants, where processes of repair go on very rapidly, the whole lens may be freely broken up. In diabetic cataract, or indeed in all cases of solution, where the patient is adolescent or adult, or the eye at all weak, only a small portion of the lens should be attacked at one sitting. The needle should then be withdrawn gradually and with great care, that the broad axis of the blade be in exactly the same position in which it entered, _i.e._ flat and parallel with the iris, lest the iris be wounded, entangled, or prolapsed. The eye is then to be closed for twenty-four hours; if there is much pain, atropia must be freely used. _Varieties in the Operation._--Some use two needles at once for breaking up the lens. Some surgeons prefer to enter the needle through the sclerotic; this complicates the operation and renders it less certain, as the point of the needle is of course out of sight in its progress between the iris and the lens. Even in children this operation requires in most cases to be repeated at least once, while in adults it may be required at short intervals for many months. 3. _By Extraction._--In these operations the lens is at once removed from the eye--