142 A MANUAL OP BACTERIOLOGY 



may be obtained from a superficial ear vein. In the rabbit 

 blood may be obtained by passing the fine point of a piece 

 of glass tubing, drawn out and bent to a convenient angle, 

 or the needle of a syringe, into one of the ear veins and 

 aspirating the blood into it. Or the vein may be punctured 

 and the blood allowed to drip into a small tube. 



Blood may be obtained from a patient for the agglu- 

 tination or the Wassermann reaction, for microscopical 

 examination, or for culture experiments, by pricking 

 the finger or the lobe of the ear or the thumb (outer 

 surface in a line with the root of the nail) with a sterile 

 needle, preferably a flat one of the " Hagedorn " type, 

 or with half a steel pen (nib) or a glass point ; for dis- 

 infection, the skin may be rubbed with a little alcohol or 

 ether. After swinging the arm and winding a piece of 

 rubber tubing round the finger or thumb and pricking 

 1-3 c.c. may generally be obtained. Larger quantities 

 must be obtained by puncture of a vein with a hollow 

 needle. The blood may be collected in a small test-tube, 

 vaccine tubes, small bulbous tubes (Fig. 7, p. 57), or 

 Wright's tubes (Fig. 36, p. 260) (see also under " Wasser- 

 mann test"). 



When small tubes with contained blood are sealed in 

 the flame, care should be taken that one end is not wetted 

 with the blood, and this dry end should be sealed first 

 so as to obtain a perfect seal. When centrifuging to 

 obtain the serum this sealed end should be placed down- 

 wards in the centrifuge " bucket." 



Organisms, in natural infections in man, are usually 

 present only in small numbers in the blood, and for 

 demonstrating them by culture methods it is necessary 

 to withdraw 2-5 c.c. from a superficial or deep vein by 

 means of a sterile syringe under aseptic conditions ; 

 superficial veins may be rendered prominent by winding 

 rubber tubing round the limb so as to obstruct the 



