INTESTINAL OBSTRUCTION — PATHOLOGY. G65 



number of the forms through which the result is reached, 

 probably not a primary morbid condition, but, as in the 

 instances of entanglement, strangulation, and volvulus, the 

 sequel of some previously existing disturbance, often of colic 

 or enteric inflammation, which during the restlessness and 

 struggling of the animal result in the production of these more 

 fatal lesions. In others, as the cases of obstruction by concre- 

 tions, the condition is usually independent and of gradual 

 development; often, however, only culminating during the 

 progress of abdominal pain, which has induced during the 

 paroxysms displacement of the concretion, terminating in 

 fatal obstruction. 



b. Causation. — The immediate production of obstruction, 

 the first step in other fatal structural changes, is brought about 

 in various ways, the greater number of which may be grouped 

 under — (1) Accumulations of matter in the interior of the 

 tube; (2) Stricture of the canal from organic disease; 

 (3) Mechanical displacement and change in connection with 

 different parts of the botuels. 



1. Accumulation of Matter in the Intestinal Tube. — (a) 

 Masses of stercoraceous material of varying bulk, often adher- 

 ing to the walls of the tube and allowing portions of the con- 

 tents to pass along ; (b) Concretions of variable form and 

 character, the product of particular dietary. Some of these, 

 both such as are composed entirely of vegetable matter, the 

 refuse and indigestible particles of grains, and such as are 

 mainly formed of mineral substances, the phosphates of lime 

 and magnesia, occasionally attain an enormous magnitude and 

 are a source of wonder as to the possibility of their existing in 

 the bowel without inducing painful symptoms. 



The position of these larger concretions is usually the great 

 bowel, in the pouches of which they may remain for years 

 without giving evidence of their existence, and are probably 

 only displaced and become impacted in some portion of the 

 canal by spasm of the tube or the tossings of the animal in 

 cases of abdominal pain. The smaller sized, from the readiness 

 with which they may be moved, are more dangerous than the 

 very large. 



2. Stricture of the Bowel from Organic Disease. — This condi- 

 tion may occur at any portion of the tube, large or small, and 



