LOCAL SYMPTOMS. 21 



then groan, break out in sweats upon various parts of the 

 skin, would attempt to lie down ; indeed, when taken to his 

 stable, he would lie down, roll, and paw, as if suffering from 

 spasmodic colic. This occurred again and again ; and upon the 

 animal being killed, the condition of the artery was discovered. 



The sudden cessation of pain in violent inflammation is much 

 to be dreaded, as it gives the practitioner good reason to suspect 

 that the vitality of the part has been lost, from the inflammation 

 having gone on to gangrene. 



The situation of pain is not always the seat of the inflam- 

 matory action, as in inflammation of the liver the pain is 

 sometimes in the off (right) shoulder, as exhibited by distinct 

 shoulder lameness. This is termed sympathetic pain, and is 

 the only example within my knowledge where this sympa- 

 thetic or reflected pain can be demonstrated, although the prac- 

 titioner may surmise that this occurs in inflammation of other 

 organs. In periodic ophthalmia it may be seen to some extent. 



The Cause of Pain. — This has been ascribed to compression 

 of the nerves of the part by congestion of the vessels and 

 effusion ; an exaltation of nervous function ; a painful stretch-, 

 ing of the nerves, arising from distension of their small nutri- 

 tious vessels ; or to impression produced on the nervi vasorum 

 by the slight dilatation and elongation of the arteries during 

 each impulse of the blood. 



In general, the intensity of the pain depends upon the 

 firmness and inelasticity of the part affected. Thus the pain 

 of laminitis is of a most excruciating character, from th& 

 inflamed tissues being confined within the horny foot. The 

 pain of open joint is also of this nature, from the firmness and 

 hardness of the tissues involved; namely, bone, ligaments, 

 synovial membrane, &c. Such structures as these, along with 

 tendons and faschiae, possessing little sensibility during health, 

 in disease become extremely sensitive, and the pain in them 

 is often of an agonizing character. Dr. Lionel Beale has 

 demonstrated that in textures which in health exhibit but 

 slight sensitiveness, and become eminently so when inflamed, 

 there is a very great increase in the germinal matter which 

 they contain, and that this often proceeds to such an extent 

 during inflammation that the ramifications of the nerves appear 

 as lines of masses of germinal matter ; so that in tissues 



