WASSERMANN AND OTHER COMPLEMENT FIXATION TESTS 



2 33 



line toward the rabbit's head. The scissors must be kept between the skin and 

 superficial fascia. When the skin has been divided from the sternum to the 

 chin, it is rapidly dissected back until the anterior half of the rabbit's neck is 

 denuded. The rabbit is then grasped by the hind legs, held vertically over a 

 Petri dish so that the blood will flow directly into it when the jugular veins are 

 cut. Care must be taken to avoid opening the trachea or esophagus when in- 

 cising the jugular veins (Fig. 42). 



FIG. 42. BLOOD FLOWING FROM INCISED JUGULAR VEIN OF RABBIT INTO PETRI DISH. 



The Petri dishes containing the blood are covered and placed in a refrigerator 

 for from 12 to 24 hours. At the expiration of this time the Petri dishes are re- 

 moved from the refrigerator and the serum (fluid) is transferred to tubes and 

 centrifugalized until perfectly clear and free of suspended matter. It is then 

 transferred to clean tubes which are placed in a water bath at a temperature 

 of 55C. or 56C. for }/% hour. When removed from the water bath about i per 

 cent, of chloroform is added to the serum and it is then put in i-cc. capacity 

 vials which are tightly stoppered with rubber plugs, then stored in a refrigerator. 



