OBTAINING BLOOD IN MAN 



which have already been mentioned in connection with intravenous in- 

 jections. A simple, large, hollow needle is all that is required. Suction 

 with a syringe is superfluous. Only in Morgenroth's method of removing 

 blood directly from the heart of guinea-pigs is aspiration necessary. From 

 rabbits enough blood can be collected by making an incision into the vein 

 along its long axis with a sharp knife, or by dividing the vein transversely 

 with the scissors. The blood thus collected is not absolutely sterile. 



In man, if only a small quantity of blood is required, it can be obtained 

 from the finger or ear. If, however, a larger amount is necessary, puncture 

 of one of the veins in the bend 

 of the elbow with the Strauss 

 canula is resorted to. It goes 

 without saying that this area 

 must be properly disinfected 

 with soap and water, ether, 

 alcohol or sublimate solution. 

 Wright's method for collect- 

 ing moderate quantities of 

 blood will be reviewed in the 

 chapter on opsonic studies. 



If the vein is prominent, 

 the canula is thrust into the 

 vein directly through the skin. 

 Here the author has found it 

 more convenient to point the 

 canula upward, i.e., in the 

 direction of the blood stream. 1 

 In cases where the vein does 

 not stand out it can be made 

 to do so either by applying 

 pressure with the finger upon its central part or placing a tight rubber 

 bandage or rubber tube about the arm. This should not, however, be 

 tight enough to obliterate the radial pulse. In very fat individuals, 

 occasionally even these means may not suffice so that the vein must be 

 dissected free and incised. After completion of the venesection the arm 

 is elevated, slight pressure made upon the wound with sterile cotton 

 and a bandage applied. If a small amount of blood is sufficient, and, 

 as in most serological examinations absolute sterility is 

 not essential, venesection can be replaced by the method of 



FIG. 6. Puncture of vein. (Original.) 



Wet-cupping. 



wet-cupping. For this procedure a scarifier and Bier cup 

 are required. The technique is as follows (Fig. 7). 



1 The editor has found that more blood is obtained by thrusting the canula into the vein in 

 the reverse direction. 



