The development of perigastritis is an important factor in the spread of carcinoma, since the morbid growth rapidly infiltrates the newly formed connective tissue, and thus extends by direct continuity into the wall of the attached structure. In this manner fresh foci are constantly forming at the base of the disease and infecting new systems of blood-vessels and lymphatics. If the intestine happens to be involved, the neoplasm either compresses its lumen and occasions symptoms of obstruction, or it gradually destroys its coats, with the ultimate production of a fistula. Finally, implication of the lymphatic vessels of the peritoneum may lead to general carcinoma of that serous membrane and of the pleurae, or, should the receptaculum chyli be attacked, the materies morbi may gain an entrance to the general circulation.

Fixation of the stomach to an organ in its vicinity tends to trammel its movements and so to increase its tendency to dilatation. This result is especially noticeable in cases of adhesion between the pylorus and the liver, since the weight of the viscus dragging upon its fixed point produces a kink, which greatly hinders the propulsion of the chyme into the intestine ; indeed, this form of obstruction is responsible in great measure for the gastric dilatation that usually accompanies non-stenosing carcinoma of the pylorus or first part of the duodenum. Similarly, the contraction of adhesions between the cardiac end of the stomach and the liver or pancreas often twists and obstructs the lower end of the oesophagus; while universal adhesion of the abdominal viscera may compress the stomach and greatly reduce its cubic capacity. In not a few cases the formation of adhesions is also responsible for certain difficulties of diagnosis. Thus, it is not uncommon for the pylorus to be drawn up beneath the liver so as to obscure the existence of a tumour, and for compression of the bile duct or portal vein to occasion early jaundice or ascites, and in this way to distract attention from the primary complaint. On the other hand, peritoneal adhesions perform the useful part of limiting the diffusion of the gastric contents in cases of perforation, and thereby of preventing general peritonitis.