GENERAL DISEASES OF THE LOCOMOTORY APPARATUS 133 



possible through the iiianiier in which the skeletal imiscles are 

 inserted into the long bones, by which the lever motion is pos- 

 sible. A muscle originating on one bone and terminating on 

 another either moves both bones toward each other or, if one 

 attachment is fixed, the movable is drawn toward the fixed part. 



We maj class muscles as striated or voluntary and unstriated 

 or involuntary. A third class, rnixed, is represented by the heart 

 muscle. The striated is represented by the skeletal muscles, and 

 the unstriated by the thin muscular layers that form part of the 

 wall of the stomach, intestines, bladder and other hollow organs. 



Rheumatism. — This is an inflammation of the tissues that 

 form the locomotory apj)aratus. The effect of cold on the 

 muscles and tendons is an important factor in its production. 

 It differs from other inflammations by shifting from one part 

 to another. It is termed muscular rheumatism w^hen it afl'ects 

 the muscles, tendons and fascia, and articular rheumatism when 

 it involves the articulations. A second classification, acute and 

 chronic, depends on the character of the inflammation. The 

 muscular form is common in horses, dogs and hogs, while the 

 articular form more commonly affects cattle. 



The following causes may be considered. Animals that are 

 exposed to cold, wet, changeable weather, or kept in cold, damp, 

 draughty quarters frequently suffer from rheumatism. Under 

 such conditions it is very probable that imperfect metabolism of 

 body tissue occurs, and certain toxic products that are capable of 

 irritating the muscles and articulations form. Clinical symp- 

 toms, and the presence of bacteria in the inflamed tissue indi- 

 cate that bacteria and their toxins play an important part in the 

 development of articular rheumatism. Heredity is said to be 

 an important predisjDosing factor. One attack always predis- 

 poses the animal to a second. 



The symptoyns vary according to the severity of the attack. 

 Local rheumatism is not accompanied by serious s^anptoms. The 

 regions most commonly involved in local, muscular rhemnatism 



