170 DISEASES OF THE HOG. © 
CHAPTER XIX. 
RHEUMATISM. 
This is a very common disease among pigs, espe- 
cially young ones. It is a constitutional disease 
attended by a peculiar irritation or it might be 
called an inflammation to which all parts of the 
body are liable, but it is found most frequently in 
the hind legs. It is found in two forms, muscular 
and articular, the former when it affects the tissue 
of the muscle, and the latter when it affects the 
structures composing the joints. The nature of 
rheumatism is not well understood. The profes- 
sion is divided as to what it really is; some say the 
offending matter is lactic acid, others that it is 
uric acid, but none of these substances have been 
found in sufficient quantities to cause it. Wood 
says of this disease: “All that we know of the 
real nature of this disease is that it is peculiar, and 
that it owes this peculiarity, not to the character 
of the cause, but to some unexplained condition of 
the system called the rheumatic predisposition or 
diathesis. I am inclined to the opinion that this 
diathesis is in itself a morbid state, in fact, the 
true disease, and that the irritation and inflamma- 
tion by which it is recognized are merely symp- 
