138 SPRINGTIME SURGERY 



to attend cases of parturition. Obstetrical cases 

 in addition to the general practice entails the ex- 

 penditure of considerable energy and the prac- 

 titioner may not be as careful and observing in 

 some cases as he should be. 



Atresia Ani is a malformation that is not rare 

 and is frequently not observed by the attending 

 obstetrician. This malformation is the result of 

 imperfect union of tissues. During the earlier 

 stages of development, i. e., the embryonic period, 

 the digestive tract from the pharynx to the rec- 

 tum inclusive is formed from the entodermal 

 tube. The anus is formed in the fetal stage by 

 invagination of the skin surface, the anus and 

 rectum are at this stage separated by a thin 

 membrane. Normally the rectal and anal walls 

 fuse, the separating membrane is absorbed and 

 thus there is produced a continuous canal. 



Failure of the anal invagination, failure of 

 fusion of the anal and rectal walls, or failure of 

 solution of the separating membrane would re- 

 sult in an imperforation and there would be no 

 outlet for the escape of the contents of the diges- 

 tive tube. 



