GENERAL PATHOLOGIC CHANGES 231 



are also present and may be cultured. This condition is called 

 bacteremia. Both of these conditions are observed in a large 

 number of infectious diseases, e.g., anthrax and strangles. 



Pyemia refers to the presence in the blood of pus-producing 

 organisms which congregate to form multiple abscesses about 

 the size of a pea in different organs of the body. It often follows 

 septicemia so is considered a secondary disease. 



Sapremia is the result of absorption of poisonous putrefactive 

 products derived from the destruction of necrotic tissues, e.g., 

 gangrene and retained placenta. 



Dropsy is a pathologic condition closely associated with 

 alterations in the blood. It may be defined as a collection of an 

 excessive amount of a watery, straw-colored fluid in any body 

 cavity or tissue. The horse is less commonly afflicted than 

 sheep and other animals. Two common forms of dropsy are 

 ascites and hydrothorax. 



Ascites is an accumulation of dropsical fluid in the abdominal 

 cavity. It is caused by anything that interferes with free circu- 

 lation of the blood, so that the blood is dammed back into the 

 veins. The fluid constituents of the blood escape through the 

 uninjured vessel walls. Anything that alters the character 

 of blood or destroys the corpuscles may be responsible for as- 

 cites. The chief symptoms are distention of the belly and 

 marked swelling of the limbs. Treatment consists in abundant, 

 nutritious food, iron tonics, and drugs to act on the kidneys 

 to induce the urine to flow more freely. Tapping the animal to 

 permit the fluid to escape is often necessary, but affords only 

 temporary relief. 



Hydrothorax is a complication of certain forms of pleurisy. 

 It is characterized by an accumulation of fluid in the thoracic 

 cavity. When present, this form of dropsy may be diagnosed 

 by tapping the lower part of the chest wall. If the ear is placed 

 over the chest a sound resembling that of drops of water falling 

 into a well may be heard. 



INFLAMMATION 



Inflammation is the one constant factor in all pathologic 

 changes. By its aid the body overcomes disease, heals wounds, 

 and unites fractured bones. It is a complicated process accom- 

 panied by changes in both the blood and cells of the affected part. 



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