DISEASES OF HEART, BLOOD VESSELS, AND LYMPHATICS. 81 



CYANOSIS. 



Owing to the most prominent symptom, this condition is also called 

 " blue disease." It is seen occasionally in new-born calves. It is 

 recognized by the blue color of the mucous membrane (easily seen by 

 looking within the mouth and nostrils) , the coldne.ss of the surface of 

 the body, and rapid, labored breathing. It is due to nonclosure of 

 the foramen ovale, connecting the right with the left side of the heart, 

 and the consequent mixing of the venous with the arterial blood. 

 Calves so affected live but a short time. 



MISPLACEMENT OF THE HEART. 



Cases are recorded in which the heart has been found out of its 

 natural position, sometimes located outside of the chest. This is a 

 congenital condition, for which there is no remedy. A heifer calf 

 with the heart entirely outside of the thoracic cavity and contained 

 beneath the skin in the lower part of the neck was kept at the veteri- 

 nary hospital of the University of Pennsylvania for two years, during 

 which time it matured into a well-developed cow. 



W^OUNDS OF ARTERIES AND VEINS. 



When a blood vessel is opened it may be told at a glance whether 

 it is an artery or a vein by simply bearing in mind that bright-red 

 blood comes from arteries and dark-red from ^eins. When a vein or 

 a very small artery is severed the blood flows from the vessel in a con- 

 tinuous and even stream, but when one of the larger arteries is severed 

 the blood comes from it in intermitting jets, or spurts, corresponding 

 to the beats of the heart. It is well to call attention to the fact that 

 the dark-red blood which flows or oozes from a wound soon becomes 

 bright-redj because it gives up its carbonic-acid gas to the air, and 

 absorbs oxygen gas from the air, which is exactly the change it under- 

 goes in the capillaries of the lungs. 



The general treatment of wounds will be found in another section; 

 here it is only necessary to refer briefly to some of the most practical 

 methods used to arrest hemorrhages, as instances occur where an 

 animal may lose much strength from the loss of blood, or even bleed 

 to death unless action is prompt. 



BLEEDING ( HEMORRHAGE) . 



The severity of a hemorrhage depends upon the size of the vessel 

 from which the blood escapes, though it may be stated that it is more 

 serious when arteries are severed. If the wound in an artery is in the 

 direction of its length, the blood escapes more freely than if the vessel 

 is completely severed, because in the latter instance the severed ends 

 retract, curl in, and may aid very much in arresting the flow. AATien 

 16923°— 12 6 



