136 THEORY AND PRACTICE 



solve SO that the salts of the intestinal juices will form around 

 it until it grows to a very large size, and attains a great w^eight. 

 Starting small in this way, the calculus forms a pocket, the lining 

 of which becomes irritated, not enough to do any harm but 

 enough to set up a sub-acute inflammation that runs into a 

 chronic. The result is cell proliferation of connective tissue 

 which forms a fibrous pocket which gradually becomes accus- 

 tomed to the growing calculus. The calculus does no particular 

 harm unless it rolls out of the pocket. 



The "dust balls" usually form in animals feeding on mill 

 cleanings from which they get dust and chaff of various kinds. 

 These balls are light and usually round and of a black color, — 

 most always black. Sometimes these balls form in considerable 

 numbers, a half dozen in one animal. 



Stricture. — In this condition you must bear in mind that there 

 is likely to be cell proliferation and inflammation. The forma- 

 tion of fibrous tissue thickens the wall of the intestines and de- 

 stroys its dilatability, producing more or less stenosis. Some do 

 not reduce the size of the tube while others reduce it to almost 

 nothing. Strictures of this kind might produce a fatal obstruc- 

 tion in the bowels. 



Volvulus. — This is sometimes called gut-tie or gut-twist. 

 The word means a turning around. There are two ways in which 

 the volvulus occurs: 1. In one case a portion of the intestine 

 seems to turn right around on itself, making from one to four 

 turns; this is fatal by strangulation. 2. In the second we have 

 a rupture of the mesentery as a result of more or less degenera- 

 tion, and in this degenerated condition if the horse rolls, a por- 

 tion of the bowel passes through the rupture making a twist on 

 each side of the hernia. This causes strangulation. This is 

 fatal. 



Intussusception. — This is an invagination of a portion of a 

 bowel into another portion of itself. This apparently should 

 occur often, yet it does not, much to our surprise. It never oc- 

 curs under normal conditions. In order to bring it about there 

 must be a dilatation of a part, which is probably due to a minor 

 amount of degeneration with relaxation, naturally causing the 

 wall to dilate. When this takes place, the motion of the intes- 



