DIAPHRAGMATIC HERNIA. 49 



the small colon, may appear on the floor of the thorax in either of the 

 pleuritic cavities, — oftenest, however, in both, the resistance of the 

 posterior mediastinum being very rapidly overcome. 



Whatever the variety of hernia, a hernial sac is never seen ; the 

 displaced organs are directly in contact with the pleura, and in herniae 

 of long standing adhesions usually occur between the organs and the 

 costal, pulmonary, or mediastinal pleura. The pleural and peritoneal 

 sacs may contain a certain quantity of serosity, but abundant exudate 

 is rare, save after complications due to engorgement or strangula- 

 tion. 



The dimensions and shape of the diaphragmatic opening vary 

 greatly. In recent hernia the margins are red, ecchymosed, and in- 

 flamed ; in those of long standing thickened, more or less fibrous, and 

 less vascular. 



The gravity and character of the symptoms depend greatly on 

 whether the condition is recent or of old standing, and on the volume 

 of the organs which have entered the thorax. 



Recent large hernia; produce violent colic. The animal then exhibits 

 an anxious look, the eyes are widely opened, the nostrils extremely 

 dilated ; the respiration is markedly difficult, irregular, and jerky. 

 When the volume of the hernia is small the symptoms are much less 

 alarming and significant, consisting chiefly in depression, failure of 

 appetite, and slight colic. The breathing shows little change, though 

 as a rule it is short, and expiration is double. 



Large chronic hernia; are accompanied b}- irregularity of the pulse. 

 During work the animals soon become exhausted and "blow." It has 

 been noticed that animals with unilateral herniae always lie down on 

 the same side as the hernia. If the herniated parts are of small size 

 there may be no readily appreciable symptoms so long as the digested 

 material and the blood circulate freely, and the animal may continue 

 to do ordinary work for a long time without showing serious dis- 

 turbance. A number of cases show this. Engorgement and strangu- 

 lation, however, readily occur in such concealed hernia;, because the 

 diaphragmatic opening is almost always of small dimensions. Com- 

 plications of this kind are possible in all old-standing cases, and are 

 announced by the same symptoms as obstruction (" stoppage") of the 

 bowel. 



The first series of symptoms produced by diaphragmatic hernia 

 may be summed up as follows : — colic, great anxiety, dyspnoea, irre- 

 gularity, jerkiness, and doubling of the expiratory movement. 



When hernia is suspected, auscultation and percussion greath' 



D 



