chap, xvi.] HERNIA 309 



intestine is found to occupy a large sac of the peri- 

 toneum, the open orifice of which is placed at the in- 

 ternal inguinal ring. The neck of the sac is long and 

 narrow, the parts around have not been disturbed to 

 perinil the bowel to pass, and the actual sac itself is 

 very thin. It is on account of these anatomical con- 

 ditions that the effects of strangulation fall as a rule 

 heavier upon this form of hernia than upon the corre- 

 sponding acquired form. 



(2) When the process is closed only at the internal 

 ring the unduly large tunica vaginalis is found to ex- 

 tend up to that orifice. Behind this abnormal tunica a 

 diverticle of peritoneum is drawn down into the scrotum 

 by the gubernaculum, and becomes the sac of a hernia 

 (Lockwood). This is known as an infantile or en- 

 cysted hernia. In such a case the abnormal tunica 

 vaginalis lies in front of the sac, and therefore three 

 layers of peritoneum would have to be cut through be- 

 fore the gut could be reached. The term " infantile " 

 was given to this rupture because the first cases re- 

 ported were met with in infants ; the term "encysted," 

 because the hernial sac was considered to be enclosed by 

 the sac of the tunica vaginalis. The condition of parts 

 that favours the development of this rupture serves also 

 to explain those anomalous cases of congenital hernia 

 that appear suddenly and for the first time in adult 

 life. Here, under some unwonted exertion the peri- 

 toneum that separates the large tunica vaginalis from 

 the general peritoneum at the internal ring gives way, 

 and the gut at once passes into the cavity beyond, and 

 so appears in the condition of a congenital hernia. 



The infantile hernia must also include cases in 

 which the sac descends behind an entirely unclosed 

 vaginal process. 



(3) In the last-named circumstance a tubular pro- 

 cess of peritoneum leads down as far as the top of the 

 testicle, and there ends, the normal tunica vaginalis 



