It is unnecessary to describe this apparatus any further, for it was found by myself and others that it could be with advantage modified in the direction of simplicity. It is in the first place unnecessary in drawing the blood to create any negative pressure if a needle of a large enough bore (2 or 3 mm.) be used, and, further, it is an advantage not to have the needle attached in any way to the bottle, which, as the blood flows into it, has to be freely agitated in order to mix the blood quickly with the citrate. The needle may, therefore, be attached to a rubber tube of suitable length which hangs freely into the collecting vessel as shown in the diagram on p. 127. The third tube of “Robertson’s bottle” may be dispensed with by using a conical flask provided with a side tube to which a rubber bellows can be attached. The delivery tube is therefore the only one that need pass through the rubber bung. This tube should have an angle in it inside the flask so that its lower end reaches into the corner, and the extremity should be ground down obliquely so that, although it reaches right into the corner, it does not become occluded by too accurate contact with the surface of the vessel. By this means any wastage of blood is prevented. I have found it a very great convenience to introduce into the delivery tube just outside the flask an air-lock,[8] the value of which will be seen shortly. To the barrel of this air-lock a rubber tube with a cannula is attached. Close to the cannula is some form of clip. The whole apparatus is illustrated in the figure on p. 133, and with the help of this its use may be readily understood. [Illustration: Fig. 9.--TRANSFUSION NEEDLE (ACTUAL SIZE)]