Etiology. Pathogenesis. Anatomical Changes. 359 



rapidly or are overworked shortly after feeding. Dogs are 

 sometimes bloated after the abmidant ingestion of starchy food. 

 Abundant stuffing of parts of the intestines with thick mashy 

 feces favors the collection of gases in the parts nearest to the 

 stomach. 



It sometimes happens that cribbling horses swallow enough air on 

 feeding to produce bloating, and it is claimed that this may also occur 

 if these animals move rapidly towards the wind. While the first mode 

 of formation of moderate bloating may be conceded, the second one can 

 hardly be accepted as probable. 



Secondary bloating occurs in various forms of closure of the 

 intestines in grave thrombotic-embolic disease of the intestine; 

 and in the course of diffuse acute peritonitis, in internal strangu- 

 lation, volvulus and thrombosis of the mesenteric vessels, bloat- 

 ing appears early after a few hours in the affected loops of in- 

 testines, while anteriorly to the obstruction, as in other cases 

 of secondary bloating, this condition develops slowly and only 

 rarely reaches a high degree during the life of the animal. 



Pathogenesis. A portion of the feed swallowed ])y horses 

 gets from the stomach into the small intestines even during 

 feeding and from there soon into the large gut. According 

 to Scheuner and Grimmer corn gets into the large intestines 

 two hours after ingestion, hence fermentable feed can form 

 gases, very shortly after ingestion, along the whole intes- 

 tinal tract with the exception of the rectum and also to a mod- 

 erate extent in the stomach. In consequence of stretching and 

 by chemical influences (carbon-dioxide, methane, fatty acids) 

 the muscularis of the stomach and intestines is irritated 

 to frequently recurring convulsive contractions which in their 

 turn produce colicky pains. The strong contractions and 

 the absorption of the gases by the blood at first prevent great 

 stretching of the intestines, but these means are insufficient to 

 absorb all of the rapidly forming gas. Loops of intestines, there- 

 fore, become more and more dilated; these, as Avell as the whole 

 intestinal tract, suffer in contractility while compression of 

 blood vessels occurs likewise, further preventing the absorption 

 of gases. The dilated intestines also press the diaphragm to- 

 ward the thorax and the negative intrathoracic pressure is 

 diminished, the cardiac diastole becomes interfered with and 

 the blood pressure in the arteries is lowered. 



In hogs and dogs bloating is developed similarly though 

 generally somewhat later after food ingestion. 



Anatomical Changes. On postmortem examination the ab- 

 domen is occasionally dilated and very tense, the more so since 

 fermentation and the formation of gases continue after death. 

 The dilated and tense loops of intestines are pressed out with 

 great force after opening up the abdominal cavity. If rupture 



