166 SWINE PRACTICE 



but in the older lesions there may be a distinct capsule. Superficial 

 necrotic foci may be associated with pleurisy. 



Symptoms. — The first symptom evidencing septic pneumonia is 

 the foul-smelling exhaled air. This symptom does not occur in ail 

 cases, as the escape of putrid odors is dependent upon the erosion 

 and discharge into the bronchial tubes of necrotic putrid material. 

 Rise of temperature accompanies practically all eases of septic pneu- 

 monia. The fever may be irregular and intermittent, the thermal 

 disturbance depending upon absorption of septic products. In those 

 cases of croupous pneumonia in which septic pneumonia is a sequel, 

 the general symptoms will be the same, plus the offensive breath, as 

 those observed in a case of croupous pneumonia. A microscopic 

 examination of the nasal discharge will reveal the presence of shreds 

 of disintegrated lung tissue in eases of septic pneumonia, which fact 

 is of diagnostic value. The course of septic pneumonia is uncer- 

 tain. The attack may terminate fatally in two or three days after 

 the onset of the disease or, if the septic lesions are limited in extent, 

 they may become encapsulated and the animal recover, the length 

 of time required varying from a few weeks to as many months. 



Treatment. — Remedial agents are of little, or no value so far as 

 the septic process is concerned. The treatment of symptoms as they 

 develop will be of some value. The animal should be given good 

 care and sanitary surroundings provided. 



Interstitial or Chronic Pneumonia 



Interstitial pneumonia is a chronic condition characterized by pro- 

 liferation of fibrous tissues. This condition is usually a sequel to 

 chronic catarrhal bronchitis and chronic bronchopneumonia. It is 

 observed in swine in those sections of the country where it is con- 

 tinuously dusty and in swine kept in quarters where slightly irri- 

 tating gases prevail. 



Etiology. — Constant inhalation of mild irritants, such as dust or 

 chemical fumes. 



Lesions. — Fibrous proliferation characterizes this disease. The 

 fibrous tissue forms around the bronchioles, the process gradually 

 extending and involving the alveoli. The bronchioles and alveoli 

 also show evidence of catarrh. The affected lung is dense, and when 

 cut offers more resistance than the normal lung. The degree of 

 fibrous proliferation is quite variable in some instances; there is a 



