450 G-ENERAL DISEASES. 



The mode by which the influenza of the horse is propagated is 

 entirely unknown. Trashot states that he has often tried to 

 produce the disease by inoculating with the blood, with the dis- 

 charge from the nose, and with other products ; but always in vain. 



For safety's sake, it is well to isolate, for at least a week, even 

 apparently sound horses which have been recently brought from 

 districts in which influenza is rife, before they are allowed to enter 

 stables containing healthy horses. 



Stallions which have had influenza, sometimes remain capable 

 of infecting mares they cover, for several months after they have 

 apparently regained perfect health. 



Although the type of influenza varies greatly, both in individual 

 cases and in different outbreaks ; the cause of the disease appears 

 to be the same in all, however dissimilar may be its manifestations. 

 Symptoms of catarrh may be prominent in one case, or in one 

 epizootic; those of bowel disorder in another; and symptoms of 

 rheumatism may manifest themselves indiscriminately. 



VARIETIES. — Influenza may be roughly divided as follows: — 

 (1) simple catarrhal influenza ; (2) pink-eye ; (3) abdominal or 

 enteric influenza ; (4) rheumatic influenza. 



Some authorities consider that when the mucous membrane 

 which lines the eyelids, presents a pink appearance, the disease is 

 a different one from the simple catarrhal form ; while others hold 

 that pink-eye is but an aggravated variety of the catarrhal form. 

 For convenience' sake, I shall adopt the catarrhal view. This 

 peculiar colour of the inside of the eyelids was a marked symptom 

 of the great epizootics which appeared during 1877 and 1882-3 in 

 England and Scotland. In the bowel form, which is the gravest 

 of all, the mucous membrane of the eyelids is of a brick or orange 

 red. Hence, it would appear that the colour of the mucous mem- 

 brane is regulated rather by the severity of the attack, than by 

 any difference in the exciting cause of the disease. 



DISTRIBUTION.— Influenza is well known throughout the 

 United Kingdom, North America, the Continent, and, to a less 

 extent, in India. 



DURATION. — The acute stage usually runs its course in less 

 than a week. When there are no complications, recoverv is 

 generally complete within a fortnight. 



IMMUNITY acquired from one attack may last from one to six 

 years. 



