Frequent as ulceration of the mucous membrane is in fever, and characteristic as this lesion is of the febrile state, yet it sometimes appears to be present when it does not really exist. From the quantity of adventitious matter deposited beneath the mucous coat, its surface sometimes becomes irregularly elevated, its valvulæ conniventes obliterated and its aspect smooth and glistening: in this state it may be easily mistaken, on a superficial examination, for ulceration, while more careful observation will shew that the membrane itself remains entire. Proportioned to the extent and degree of these changes in the intestine are, inflammation, enlargement, induration and suppuration of the mesenteric glands; and invariably those glands which are embedded in that portion of the mesentery attached to the affected intestine, are the most diseased. It is quite remarkable with what uniformity the spleen is diseased in fever. In almost every case of genuine fever hitherto examined, it has been found altered in appearance and deranged in structure. Its natural purple colour is changed to a deeper and darker tint, and, on the removal of the peritoneum that invests it, its substance, on being slightly touched with the finger, breaks down into an almost fluid mass. The pancreas, the structure of which is so seldom changed in any other disease, is very constantly deranged in fever. Its morbid condition is invariably the same, and, what is singular, it is exactly the reverse of that produced in the spleen. It is always more firm than natural; often it is exceedingly indurated, and that portion of it which is attached to the duodenum is sometimes nearly cartilaginous. Each organ having been described in the order of the frequency and extent of the disease it exhibits, we have hitherto said nothing of the mucous membrane of the stomach. This viscus having been regarded in France as the great source and seat of fever, particular attention has been paid to the appearances it exhibits after death. The uniform result of the most careful examination of fatal cases in London is, that the mucous membrane of this organ is less frequently, less severely, and less extensively diseased than any other portion of the same membrane. Occasionally it is more vascular than natural; this vascularity is seldom general; it is almost always confined to its pyloric half; in the few cases in which it has been very great, the membrane has been observed to be thickened and sometimes softened: but no instance has occurred in which it has been the seat of a single ulcer.