_Cocaine_ and other solutions used at the time and subsequently to operation should be sterilized. To ensure this the solutions should either be boiled immediately before use, or put up in drop bottles made in one piece with a long tapering neck, which is sealed off, and can be broken immediately before use. These bottles can be kept in an aseptic solution so as not to soil the hands of the surgeon. _The hands_ of the surgeon are purified. After the dressings have been removed, the patient’s head and the area surrounding the operation are covered with sterilized towels. In operations such as advancement, where sutures are used, it is desirable that the face should be covered with sterile muslin, with a hole cut in it for the eye, so as to prevent the sutures being contaminated from the skin of the face. The eyelids are again washed in 1-2,000 perchloride of mercury lotion, and the conjunctival sac is washed out with a strong stream of boric lotion or normal saline by means of a sterilized irrigator or an undine (Fig. 77) which has been kept in a bowl of lotion. _Instruments._ Non-cutting instruments are boiled for 15 minutes in distilled water and placed in a tray of 1-80 carbolic lotion. Some surgeons prefer to place the instruments in the tray without lotion on sterile wet lint, as this excludes infection from the surgeon’s hands due to the lotion running off them on to the instrument. Failing distilled water, a small quantity of soda may be added to the water used for boiling, but this has the disadvantage that a deposit is liable to form on the instruments. This may be obviated to a certain extent by not placing them in the solution until it is boiling. Cutting instruments should be sterilized by dipping them in liquefied carbolic acid (crystals dissolved by heating with 10% of water) for half a minute immediately prior to use and then into absolute alcohol to remove the acid; they are then placed in the tray. The greatest care should be taken to see that cutting instruments and needles do not touch the side of the dish. The edges and points should always be carefully tested immediately before sterilization on a drum covered with fine kid specially made for the purpose. The points should pass through the drum by the weight of the instrument held flat on the open palm; the cutting edge should also be tested. Scissors are best tested by cutting wet cigarette paper, special care being taken to see that the edges are good near the points. Immediately after operation the instruments should be boiled, and dried whilst hot in order to prevent rust. [Illustration: FIG. 78. CATARACT EXTRACTION. The drawing shows the line of incision. Note the conjunctival flap.]