DISEASES OP RESPIRATORY ORGANS 149 



in swine because of the small size of the opening of the nostril. 

 Hydrogen peroxide may be introduced by means of a syringe, and 

 this gives immediate and sometimes permanent relief. A solution 

 of adrenalin chlorid gives similar results. 



CATARRHAL RHINITIS 



Catarrhal rhinitis is a common condition in swine. It occurs in 

 pigs and mature swine. It is probably more prevalent in the breeds 

 of swine that have dished faces. This, like other inflammatory 

 disturbances of the respiratory tract, is more common in early spring 

 and late fall than in summer or winter. Catarrhal rhinitis may be 

 acute or chronic. 



Etiology. — Catarrhal rhinitis in swine is usually caused primari- 

 ly by some non-infectious irritant, although in the later stages micro- 

 bian agents may, and frequently do become of first importance. 

 Swine that are permitted to sleep in straw piles or manure heaps 

 during cold weather are very prone to rhinitis because they become 

 heated and when they come out in the morning they chill. Ammonia 

 fumes may prevail in manure heaps in sufficient quantities to be 

 irritating when inhaled. Dust when inhaled produces an inflam- 

 mation of the Schneiderian membrane. In general, catarrhal 

 rhinitis is caused by inhalation of irritating substances, such as dust, 

 ammonia or other chemicals and by sudden temperature changes. 

 This condition is frequently found associated with other diseases, 

 particularly swine plague and hog cholera. 



Lesions. — Acute catarrhal inflammation of the nasal mucosa is 

 characterized by congestion and tumefaction of the mucous mem- 

 brane. This membrane is at first dry, but later varying quanti- 

 ties of serous fluid and mucus escape upon the surface of the 

 mucosa and are discharged, some of the discharge accumulating 

 upon the external surface of the nostril. The exudate may become 

 infected and invaded by leukocytes, the discharge thus becoming 

 mucopurulent or purulent. Chronic catarrhal inflammation may 

 produce a hypertrophy or atrophy of the nasal mucosa. The hy- 

 pertrophic change is due to the production of large quantities of 

 fibrous tissue in the submucosa. The mucosa thus becomes thick- 

 ened, dense, and leathery. The increased volume of the mucous 

 membrane may so diminish the cavities of the nose that breathing 

 is difficult. In other instances the mucous membrane atrophies, 



