196 Anatomy of the Rabbit. 



the inner surface of the thigh and of the abdominal wall will be exposed. 

 The white cord representing the inguinal ligament lies in the bottom 

 of the inguinal furrow. Appearing from beneath the ligament in this 

 position, and passing to the surface of the thigh are the femoral nerve, 

 artery, and vein, covered by an exceedingly thin layer of muscle be- 

 longing to the sartorius. The three structures may be separated from 

 one another, and the muscle pulled away at the same time, by working 

 lengthwise along the structures with the fine forceps. The artery must 

 be thoroughly cleared for about 3 cm. from the inguinal ligament. 

 Care must be exercised in this operation to avoid breaking its branches 

 or the tributaries of the vein. The artery lies in front of the vein and 

 is distinguishable by its smaller size, flattened or collapsed condition, 

 and by its white coloration. The vein will be found greatly distended 

 with blood. The nerve lies in front and partly on the lateral side of the 

 artery. 



When the femoral artery has been fully exposed, a ligature of coarse 

 thread, previously moistened, may be passed around its base, close to 

 the inguinal ligament. An ordinary single knot may be placed on the 

 ligature, but must be left loose until the cannula is inserted. By grasping 

 the bare edge of the artery at about 2 cm. from the ligament, the 

 operator may make a V-shaped incision in the vessel with fine scissors. 

 The tips of the scissors are directed toward the ligament. The incision 

 must be clean-cut, and care must be taken not to cut more than half- 

 way through the vessel. By taking up the little angular flap with the 

 fine forceps, the cannula may be worked into the vessel and pushed 

 well down into it beyond the inguinal ligament. The knot is then 

 tightened by a gentle even pull on the ends of the thread. The knot 

 should never be pulled very tight or doubled. 



At the moment when the cannula is securely fastened into the 

 vessel, the clamp is to be removed from the connecting tube and the 

 fluid allowed to run in. At the beginning of the process a little care in 

 arranging the animal will be amply rewarded by convenience in dis- 

 section. The hind limb on the side opposite the incision should be 

 drawn backward. The front limbs should be drawn apart, so that the 

 breast is well exposed, and held in this position by a thick cord, or, better, 

 a stout flexible wire, passing around the back of the animal. The body 

 should be turned slightly to the operator's left. 



The animal is sufficiently embalmed in two hours. About eight 

 animals may be kept on the table by one operator, provided he has at 

 his disposal a sufficient number of cannulae, one for each specimen, 

 since the first may be taken off the apparatus after the eighth has been 

 put on. 



Since small difficulties frequently occur in the process, especially in 

 placing the cannulae and in keeping them clear of obstruction, a number 

 of points may be mentioned which indicate to the operator just how the 

 operation is succeeding. The entrance of the cannula into the artery, 

 in the first place, is usually accompanied by a slight rise of blood into 

 its tip. General muscle contractions in the recently killed animal are 

 a safe indication of uniform flow of the fluid to these and also other parts 



