428 INJUKIES TO THE AKTEKIES. 



the spermatic artery, no blood is lost. Incised and punctured 

 wounds are, however, not so safe as lacerated and contused 

 arterial wounds. If an artery is pricked or cut, especially in 

 an oblique or transverse direction, its elasticity tends to 

 maintain the orifice wide, and fatal haemorrhage ensues. 

 Cutting an artery across is attended with its retraction 

 within the sheath, and a stoppage of the bleeding if the 

 vessel is not too large, and a longitudinal incision may close 

 from the lips of the wound not being withdrawn from each 

 other. 



Bleeding from an artery is diagnosed by the peculiar jerk 

 of a full and regular stream of bright arterial blood, which 

 is pushed from the wound with considerable force. As the 

 animal grows feeble and faints, the flow diminishes, and the 

 jerks are more perceptible. 



The spontaneous arrest of arterial haemorrhage when an 

 artery is cut across occurs as follows: Blood enters the 

 sheath around the arterial wound so as to press on the latter; 

 the artery has a tendency to retract, and its orifice closes, 

 and the blood clots as far up as the first collateral branch. 

 This is the temporary plug which undergoes changes whilst 

 lymph is thrown out at the mouth of the wound to close it 

 by the ordinary process of cicatrisation. The clot itself 

 becomes discoloured, and the constituents that remain adhere 

 firmly to the arterial tunics. Very soon the portion of the 

 artery obliterated shrinks, unites, and is to be traced after- 

 wards as a fibrous remnant. The blood's flow is equalised 

 by the adaptation of collateral vessels. 



The arteries that have been most frequently injured in the 

 lower animals, have been the palatine, temporal, carotid, 

 metacarpal, branches of the femoral or gluteal, and meta- 

 tarsal. 



Treatment consists in ligature, pressure at a distance from 



