572 THE PRACTICE OF VETERINARY MEDICINE. 



followed by a discharge from the nose, showing increased 

 action of the raucous membranes ; and, on account of its 

 peculiarities as to symptoms, complications, etc., we may 

 regard it as a specific disease. Hence we are justified in 

 arriving at the following conclusions : That influenza can- 

 not be considered as a local disorder ; but, on the contrary, 

 it is to be regarded as a general disease. The bronchitis, 

 nasal defluxion, cough, etc., being merely the local expres- 

 sions of a constitutional aff'ection. 



It is essentially a fever of a specific character — a peculiar 

 species of fever — presenting well marked catarrhal and 

 febrile symptoms, and having for its anatomical character- 

 istic, inflammation of the great mucous track; but more 

 especially showing itself in connection with the mucous 

 membranes lining the air-passages and other parts con- 

 tiguous thereto. It is due to a specific poison which is 

 received into the system, and according to the amount 

 absorbed, the organs involved, or the susceptibility of the 

 animal to the morbific influence, are the symptoms more or 

 less developed and varied in character. 



The causes of influenza are predisposing and exciting. 



Predisposing are — sudden changes of temperature, as in 

 the spring and autumn : the disease being more prevalent 

 daring these months. 



Crowding together of large numbers of animals in 

 underground, damp, or badly ventilated stables, where the 

 air is necessarily vitiated to a great extent ; noxious 

 emanations from heaps of decomposing animal or vegetable 

 matters ; stabling or pasturing in low, swampy situations ; 

 poor food, impure water ; exposure, age, and excessive work, 

 by causing debility, render the animal more susceptible to 

 the influence. As it were, the soil is thus prepared for the 

 reception of the seed, which, in the shape of the contagious 

 principle, constitutes the ' exciting cause.' The disease also 



