THE DIGESTIVE SYSTEM. 



533 



process may extend outward so as to lead to perforation into the air 

 passages, the lungs, pleurae, pericardium, and large blood-vessels. The 

 new growth may extend outward and infiltrate the surrounding soft parts, 







FIG. 30ti. INFILTRATING CARCINOMA OF THE (ESOPHAGUS. 



so that the resophagus is surrounded by large, solid, cancerous masses. 

 Metastatic tumors are also sometimes formed. 



Cysts. Small retention cysts of the follicles of the mucous membrane 

 are sometimes found. Larger cysts of the oesophagus lined with ciliated 

 epithelium have been described. ' 



The Stomach. 



Malformations . 



Malformations of the stomach are not common. The organ may be entirely want- 

 ing in acephalous foetuses. It may be of various degrees of smallness, sometimes no 

 larger than the duodenum. It may be divided into two halves by a deep constriction 

 in the middle. The pyloric orifice may be stenosed or entirely closed. The stomach 

 may be outside of the abdominal cavity from a hcrnial protrusion through the dia- 

 phragm or at some point in the abdominal wall. It is found on the right side, instead 

 of the left, when the other viscera are transposed, and the position of the cardiac and 

 pyloric orifices is correspondingly inverted. 



Congenital stenosis of the pylorus in infants is of occasional occurrence. It is com- 

 monly due to fibrous hyperplasia of the submucosa, sometimes involving the internal 

 muscular layers. 2 



1 For recent bibliography of lesions of oesophagus see Thwel, Lubarsch and Oster- 

 tag's "Ergebnisse," Jahrg. v. for 1898, p. 128. 



2 See Meltzer, New York Med. Record, August 20th, 1898, bibliography; also Rol 

 lesion and Crofton-Alkins, British Med. Jour., 1900, vol. ii., p. 1768. 



