160 The Diseases of Animals 
the heart again. Arteries have thick elastic walls, that 
throb with the beating of the heart, and the blood is 
always under considerable pressure. If an artery is cut 
the blood is bright searlet in color and flows with force, 
coming in a full spinning stream. If a vein is eut 
the blood is dark in color and simply wells out of the 
wound with no force. In stopping a severe hemor- 
rhage, it is necessary to know whether an artery or 
a vein is severed. If an artery, the end of the blood- 
vessel toward the heart must be treated, as the blood 
comes from the heart. If a vein is cut, the end of 
the blood-vessel away from the heart must be treated, 
as the blood is flowing from the extremity toward the 
heart. If the hemorrhage is from a large blood- vessel, 
the best way to stop it is to find the cut end of the 
vessel and ligate, or tie it. This can be done by get- 
ting hold of the cut end with the fingers, pulling the 
blood- vessel out a little and tying it tightly with silk 
or linen thread or any other that can be obtained, 
provided it is clean. The thread should be tied with 
a “surgeon’s knot,” as this does not slip. Fig. 38. 
Another practicable method of stop- 
ping hemorrhage from large blood- 
vessels is to sear with a hot iron; 
but this is severe treatment, and 
should be used only when abso- 
lutely necessary. If carefully ap- 
plied to the blood-vessel itself, however, there is com- 
paratively little pain and the treatment is effective. 
For ordinary, and even for severe wounds, nature 
has an admirable way of stopping hemorrhage. The 
Fig. 38. Surgeon’s knot. 
