HEKNIA. 439 



Its lengtli exceeds its widtli, and it is somewhat depressed in its 

 center It progresses rapidly towards cicatrization, only a small 

 scar remaining, and this is readily concealed by the growth of the 

 surrounding hair. 



{d) Operation in Cases of Complications. — If the hernia is 

 irreducible and there is strangulation, the enlargement of the ring 

 must be carefully made with a curved, blunt bistoury, having a 

 short, guarded sharp edge. When the reduction is prevented by 

 adhesions, the operation necessary for their division will demand 

 the exercise of the utmost skill and caution to avoid injury of the 

 peritoneum, and there should especially be no neglect or parsi- 

 mony in respect to the employment of antiseptic precautions. In 

 fact, it would in many instances be wiser to leave the animal to 

 the resources of nature than to undertake an operation of so much 

 dehcacy and importance, and which involves so many serious con- 

 sequences, without amj)ly providing every resource of skill and 

 knowledge, and anticipating every contingency of accident or dan- 

 ger. In some cases, when the strangulation has been due to the 

 formation of gases in the protruding intestine, we have used the 

 aspirator for theii" removal, and then have met with no difficulty 

 in reducing them by the taxis. This is a means, however, which 

 is also recommended in the treatment of strangulated inguinal 

 hernia, and is discussed in the chapter appropriated to operations 

 in that region. 



Diaphragmatic Hernia. 



A diaphragmatic hernia, or diaphragmatocele, is formed by the 

 displacement of one of the abdominal organs, and its intrusion 

 into the pleural cavities, through a laceration of the diaphragm. It 

 is necessarily an accidental opening, through which such a dis- 

 placement takes place. One case is on record, and only one, 

 where the hernia passed through a normal opening, viz., the oeso- 

 phageal. 



The causes which give rise to ruptures of this kind may be 

 classilied under three heads : first, external violence ; second, pow- 

 erful contraction of the expiratory muscles while making a violent 

 effort ; and third, the exertion of force and pressure upon the dia- 

 phragm by the organs, situated on its posterior face. 



{a) External Violence. — Foremost in this category are blows 

 or contusions on the posterior costal region, such as may be made 



