48 



METHODS OF OBTAINING HUMAN AND ANIMAL BLOOD 



Sheep. Blood may easily be obtained from a freshly killed animal. 

 The first flow of blood is discarded, and a portion of the remainder is 

 collected in a large, sterile, thick-walled flask containing glass beads 



FIG. 24. A DISSECTION OF THE NECK OF A SHEEP TO SHOW THE RELATIONS OF 



THE EXTERNAL JUGULAR VEIN. 



T, trachea; O.M., omo-hyoid muscle; E.J.V., external jugular vein^ S.C.M., 

 sterno-cleido-mastoid muscle. This dissection was made soon after natural death 

 and shows the position and size of the vein with the head held backward as it is when 

 blood is removed according to the technic described in the text. When distended, 

 the vein is even larger than shown; it is quite superficial and is usually palpable when 

 pressure is made over the vein at the base of the neck. 



