5. Three yards of tape, one inch wide, and lint. 6. A silver wire suture. 7. A basin of cold water. 8. Brandy and Sal Volatile. Step 1. See that the piston-rod works properly in the syringe, and that the instrument is fit for use; then place it in the basin of cold water with the cannula to lie till wanted. Step 2. Place the person supplying the blood on a couch or easy chair in the same chamber, but so that he cannot see the recipient, lest he faint and his blood consequently flow feebly. Tie up the arm as for venesection; lay ready the lancet, and direct the assistant, in charge of the supplier of blood, to keep his thumb on the vein when it is opened, that the flow may be checked when blood is not required. Step 3. Place a tape round the arm of the recipient, above the point for injection, and another below it at a convenient distance, and lay bare a vein (usually the median basilic) for an inch and a half of its course; holding the vein by the forceps, make a slit with the scalpel and introduce the cannula, which is then intrusted to the second assistant. The stylet is withdrawn, and a minute drop of blood escapes through the cannula, showing that the point has been properly introduced into the vein. The assistant replaces the stylet and slackens the ligature, while the surgeon proceeds to fill his syringe. Step 4. The surgeon, going to the supplier of blood, makes a large opening in the vein with a lancet, or if the first assistant be a surgeon also, he may do this while the chief operator is preparing the vein of the recipient. When the vein is open and the blood flowing freely, the barrel of the syringe is inverted over it and filled with blood; when full, the nozzle is stopped by the plug and the piston attached while the syringe is carried to the recipient. Step 5. This being reached, the plug is pulled out, the nozzle inserted into the cannula, and the blood _slowly_ injected by depressing the piston gently, but without quite emptying the syringe. A minute should be spent in injecting one ounce and a half, and a pause of five minutes ensue before a second supply is introduced. This interval may be employed in cleaning the syringe, &c., and procuring a fresh supply of blood; 3-4 ounces of blood are usually sufficient, but 10 ounces have been injected on some occasions. The perturbation of the supplier (generally a near friend of the recipient), renders it necessary he should drink freely of brandy and water, that the blood flow forcibly when required. Step 6. When sufficient blood has been introduced, both patients’ wounds are dressed, as after venesection (see page 20), the long incision of the recipient being closed by a point of suture under the pad. =Tourniquets.=—Tourniquets are of several kinds. _The Ring Tourniquet_ (fig. 97) is used when pressure is desired on the main artery of such a limb as the arm. It is less easily displaced than the Signoroni, but, like that, soon becomes irksome by its continual pressure.