DISEASES OF THE HEART, BLOOD VESSELS, AXD LYMPHATICS. 81 



CYANOSIS. 



Owing to the most prominent symptoms, c3'anosis is also called 

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

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

 looking Ayithin the mouth and nostrils), the coldness of the surface 

 of the body, and rapid, labored breathing. It is caused by non- 

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

 of the heart, and the consequent mixing of the venous with the arte- 

 rial 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 even outside the chest. This is a con- 

 genital condition for which there is no remedy. A heifer calf with 

 the heart entirel}^ outside the thoracic cavity and beneath the skin 

 in the lower part of the neck was kept for two years at tlie veteri- 

 nary' hospital of the University of Pennsylvania, during which time 

 it grcAv to be a well-developed cow. 



WOUNDS OF ARTERIES AND VEINS. 



When a blood vessel is opened a glance will tell Avhether it is an 

 artery or a vein by simply remembering that bright-red blood comes 

 from arteries and dark-red from veins. When a Aein or a very small 

 artery is severed the blood flows from the vessel in a continuous and 

 even stream, but when one of the larger artenes is severed the blood 

 comes 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 red, 

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

 oxygen gas from the air, which is exactly the change it undergoes 

 in the capillaries of the lungs. 



The general treatment of w ounds will be found in another section ; 

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

 methods used to arrest hemorrhages, as instances occur in which an 

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

 to death unless action is prompt. 



BLEEDING (HE3IORRHAGE). 



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

 fi^om 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 lengih, 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. When 

 33071°— 16 6 



