INFLUENZA. 233 



lescence. 475. Complications. 476. The Liver. 477. Respiratory Mucous 

 membrane. 478. The Lungs. 479. The Alimentary Canal. 480. Bowels. 

 481. The Kidneys. 482. The Heart. 483. Hea* o/ the Mouth. 484. 

 terminations of Complications. 485. General Treatment. 486. 



471. Nature of Influenza. 



Influenza is a specific disease, characterised by febrile and catarrhal 

 symptoms, accompanied by loss of appetite, great prostration of strength, 

 and often complicated by disease of the liver, lungs and mucous, mem- 

 branes generally, and sometimes with affection of the heart or bowels. 

 In all cases the nervous system is affected to a great extent, and indeed 

 most of the more prominent symptoms may be regarded mainly as 

 results of depression of the nervous centres. The cause of this depres- 

 sion is the presence of a specific poison in the blood. 



472. Causes. 



Influenza in common with other specific diseases is developed by some 

 peculiar condition of the atmosphere which exercises an injurious in- 

 fluence on the health of animals. Atmospheric causes, though the real 

 agents in developing and spreading specific diseases are unable of them- 

 selves to generate them. 



Other debilitating or poisoning influences, such as bad ventilation, 

 dirty stables, an insufficient supply of nutritious food, bad forage or 

 debility, or on the other hand an excess of food, even though the quality 

 be good, combined with an insufficient amount of exercise, are needed 

 to aggravate the injurious atmospheric influence. Cold damp seasons, 

 especially in spring and autumn, also adversely affect the general health. 



From all or any of these causes the health is lowered. The adverse 

 atmospheric influences, whatever they may be, which tend to propagate 

 and disseminate the disease, under these circumstances find a suitable 

 medium for the development and growth of the specific organic poison 

 which is the active agent in the production of this affection. This is 

 now generally thought to be due to the action of microbes. 



Influenza is said to be, and probably is under certain circumstances, 

 infectious. Added to already existing predisposing causes, the effluvium 

 from the body and breath of a horse and still more from the bodies and 

 breath of many horses affected with this or indeed with any other 

 disease, when absorbed into the lungs or deposited on the mucous mem- 

 branes of other horses, must be a powerful determining cause in all 

 imperfectly ventilated stables. 



But the disease can hardly be in reality highly infectious, because we 

 often find its career cut short at a time when many horses are suffering 

 from it probably from cessation of the original cause. 



472 a. Necessity of watching the earliest symptoms. 



This is a disease, which above all others requires to be taken in its 

 very earliest stage. The incipient attack can be most readily detected 



