142 PBACTICE OF EQUINE MEDICINE. 



How is the condition diagnosed? 



By the suddenness of the attack, by the fever, the condition 

 and age of the animal. 



PASSIVE CONGESTION OF THE LUNGS. 



This is where there is some obstruction in the blood-vessels 

 to the outflow of blood, with the result of a damming back of blood 

 into the vessels of the lungs. 



Name the forms. 



Two forms are recognized — mechanical and hypostatic. 



Give the aetiology. 



The mechanical form is caused by some obstruction to the 

 return flow of blood to the heart, and is seen in disease of the left 

 side of the heart; old horses; then, again, pressure of tumors. 



Hypostatic congestion is due to both a weakened heart and to 

 the lying in one position for some time. 



What is seen on post mortem ? 



The lungs are large, russet-brown color, rather tough to cut 

 or tear. 



On section, there is a brown-red color, which brightens on 

 exposure to the air from the oxidation of increased amount of 

 haemoglobin. 



If a post mortem is desired, turn the animal on its back im- 

 mediately after death, and thus cause the blood to gravitate to the 

 upper part of the lungs, so as not to interfere with the examination 

 of the lower parts, which are more usually affected. 



What are the symptoms? 



Are often vague; there is difficult breathing, a cough, the 

 animal refuses to eat, the temperature varies from 101° to 102° P., 

 the pulse is irregular, and the animal is usually old and run down. 



Give the prognosis. 



Most cases get well. Those associated with chronic heart dis- 

 ease become relieved temporarily. 



Be guarded with the prognosis, as the symptoms may hang on 

 three or four days and the animal die from oedema of the lungs. 



