44 



METHODS OF OBTAINING HUMAN AND ANIMAL BLOOD 



opening the trachea and esophagus. After bleeding, the dish is cov- 

 ered or the tube plugged and set aside for the serum to separate. This 

 method is quite simple, may be employed by the inexperienced, and 

 usually yields a large amount of sterile serum. 



Second Method. The animal is fastened to the operating board and 

 the neck is stretched by placing a roller beneath it. The hair over the 

 neck is clipped close, and the skin moistened with alcohol and 1 per 



FIG. 21. METHOD OP BLEEDING A RABBIT FROM THE CAROTID ARTERY, 

 SECOND METHOD. 



cent, lysol solution. The carotid artery of one side is exposed by making 

 a straight incision through the skin over the trachea and skinning well 

 to one side, exposing the sternohyoid muscles and external jugular vein. 

 The carotid artery, internal jugular vein, and pneumogastric nerve are 

 to be found at the outer border of the sternohyoid muscles (Fig. 20). 

 By means of blunt dissection the artery is exposed and carefully isolated. 

 Two small spring clamps or hemostats are then applied close together 



