250 CHAPTER 27. 



impaired state of vitality. Hence its usual seat is in tissues of low 

 orp^anisation. 



Some scientists now believe that rheumatism is caused by a microbe, 

 and adduce some strong reasons for their opinion. 



504. Seat. 



The parts usually affected are the white fil^rous tissue covering the 

 muscles, the capsules of joints, the tendons and their sheaths, and liga- 

 ments. Occasionally the valves of the heart suffer from rheumatism, 

 not indeed directly, but secondarily from deposit of fibrin on them, 

 ■which impairs their functions ; and in some cases the coats of the 

 blood-vessels are affected, and more rarely parts of higher organisation. 



505. Characteristics. 



The chief peculiarities of the disease are the suddenness of its attacks 

 and a very remarkable tendency to shift from one part to another. 



Structures, which have been once affected, are very liable to recur- 

 rence of the disease, and after a time it may become chronic in such 

 parts. But though it may be chronic, variations in degree -will be felt 

 from time to time according to weather, health, and other changing 

 circumstances. 



506. Causes. 



Rheumatism is often caused by neglect. It is very readily brought 

 on by exposure to wet and cold, by insufficient diet, by bad stable manage- 

 ment, and by all other such causes as lower the general health. Draughts 

 are also a very common cause, especially where due attention is not paid 

 to the regulation of the ventilation. Rheumatism is also a frequent 

 sequel of any debilitating disease, especially of chest affections and 

 influenza. It is said to be hereditary, but this point is very doubtful. 



507. Symj^toms. 



A sudden and at first unaccountable stiffness in some part or other is 

 usually the earliest sign. The absence of any external cause sufficient 

 to account for the stiffness or lameness will lead us in such cases to sus- 

 pect Rheumatism. 



This suspicion, if correct, will be confirmed m a few days either by 

 the sudden disappearance of the attack, or by increase in the symptoms, 

 or by its shifting to some other part. For example, if the attack super- 

 venes on influenza, one fore leg may be found suddenly much inflamed 

 and sore to the touch from the knee downwards along the back tendons, 

 or the seat may be in the knee or any other joint, and may be accom- 

 panied by swelling, and the attack will probably be complicated with 

 febrile symptoms and short c^uick breathing. Under treatment the ail- 

 ment will probably get better, Ijut suddenly the other fore leg or perhaps 

 a hind leg mav be similarly aft'ected. 



