(2) =Necrosis.=—With all the severe cases of cell infiltration, hyperplasia of lymph follicles reaches a stage where resolution is impossible and necrosis occurs. The necrosis is partly due to the choking of the blood-vessels and partly to the direct action of the bacilli. The necrosis may involve only the superficial layers of the mucosa or it may extend deep into the muscular coat and even perforate the outer or serous coat. Usually, however, this does not extend below the submucosa, mucosa, or muscularis. Not all of the patches necessarily slough, but as a rule it is always more intense toward the ilio-cecal valve. (3) =Ulceration.=—The extent and depth of the ulcers depend upon the amount of the necrosis. Large ulcers are sometimes formed, especially in the lower end of the bowel, by the union of several. The edges are swollen and undermined. The base is usually smooth and formed of submucosa. Perforation of the bowel occurs in a small percentage of cases; more commonly the ulcers heal. The perforations may be multiple, but rarely exceed two in number. (4) =Healing.=—Cicatrization begins about the fourth week. This granulation tissue covers the floor. It is sometimes formed with connective tissue and a new growth of epithelium results. The gland is ultimately replaced by a depressed scar with a smooth, pigmented surface. The majority of deaths occur before this stage is reached. The gland structure is never regenerated. The =mesenteric glands= show intense hyperemia and later become enlarged and softened, but rarely ruptured. The glands at the lower end of the ileum are markedly involved. The =spleen= is enlarged, softened, and diffluent. Occasionally rupture occurs. Infarction is not a rare occurrence. The =liver= shows parenchymatous and granular degeneration, and the cells are found to contain much fat. Infarction abscesses and acute yellow atrophy occur in rare instances. Diphtheritic inflammation of the gall-bladder sometimes occurs and the bile is thinner and paler than normal. The =kidneys= also show parenchymatous degeneration. They are pale in appearance, with slight cloudy swelling. Microscopically, there are seen granular and fatty infiltration of the cells of the convoluted tubules. Rarely, there is acute nephritis which may be hemorrhagic. There may be miliary abscesses in which typhoid bacilli have been found by some observers. Diphtheritic, but more frequently catarrhal, inflammation of the pelvis of the kidney may occur. Catarrh of the =bladder= is not infrequent and even sometimes diphtheritic inflammation is present. Rarely orchitis is encountered. =Hypostatic= congestion of the =lungs= is not uncommon. Gangrene and hemorrhagic infarction are sometimes present. Lobar pneumonia may be a complication.