METHODS OF INOCULATION 743 



flow of blood into the syringe will indicate that the needle has entered 

 the vein. The syringes furnished by manufacturing firms are not 

 well adapted for making these injections, as the rubber plunger fre- 

 quently adheres to the glass barrel, so that the injection will be jerky 

 and difficult, and, besides, it may be difficult to determine when the vein 

 has been entered. It is better to empty the contents of these syringes 

 into a large, sterilized, glass-barreled syringe, such as the Record, Luer, 

 and Burroughs-Wellcome syringes, which have a close-fitting but easily 

 working piston, and are attached to the needle by a flange and not by a 

 screw thread. (See Fig. 8.) The needle should be sufficiently large 

 and have a sharp but short beveled edge. A long point may pierce the 

 vein through and through, and permit perivascular bleeding or result 

 in a subcutaneous injection. 



2. In young children with fat arms and a weak circulation it is usu- 

 ally necessary to expose a vein at the elbow by making a small incision. 

 In older children and adults a vein may stand out prominently enough 

 to permit the needle to be inserted directly through the skin without 

 making an incision. A firm rubber tourniquet is applied above the 

 elbow; a very simple one is constructed by a single turn around the arm 

 with a piece of ordinary soft-rubber tubing held in place by a hemostat. 

 After the vein has been entered the tourniquet should be quickly removed 

 and this is quickly and deftly accomplished by releasing the hemostat. 



3. The skin about the site of injection is cleansed with soap, water, 

 and alcohol, or merely painted with iodin, which is removed with alcohol 

 just before the injection is to be given, in order that the vein may become 

 visible. 



4. An assistant steadies the patient's arm and should be ready to 

 release the tourniquet. 



5. The operator then steadies the skin over a vein usually the 

 median basilic or median cephalic with the left thumb and forefinger, 

 and introduces the needle into the vein. A flow of Uood into the syringe 

 indicates that the vein has been entered. The tourniquet is then released 

 and the injection slowly given. Or the needle may be detached from 

 the syringe and passed into the vein; when blood appears, the syringe 

 is quickly attached and the injection made. The puncture wound is 

 then sealed with a wisp of sterile cotton and collodion or with gauze and 

 a bandage. The syringe shown in Fig. 139 is well adapted for the in- 

 travenous injection of serum, and was devised for the administration of 

 concentrated solutions of salvarsan and neosalvarsan, but any reliable 

 and large glass-barreled syringe may be used. 



Gravity Method. Larger quantities of serum or other fluid are 



