3d. From the sameness of the food and form, the action of the poisonous gases in the densely crowded and filthy stockade and hospital, the blood was altered in its constitution, even before the manifestation, of actual disease. In both the well and the sick red corpuscles were diminished; and in all diseases uncomplicated with inflammation, the fibrous element was deficient. In cases of ulceration of the mucous membrane of the intestinal canal the fibrous element of the blood was increased; while in simple diarrhea, uncomplicated with ulceration, it was either diminished or else remained stationary. Heart clots were very common, if not universally present, in cases of ulceration of the intestinal mucous membrane, while in the uncomplicated cases of diarrhea and scurvy, the blood was fluid and did not coagulate readily, and the heart clots and fibrous concretions were almost universally absent. From the watery condition of the blood, there resulted various serous effusions into the pericardium, ventricles of the brain, and into the abdomen. In almost all the cases which I examined after death, even the more emaciated, there was more or less serous effusion into the abdominal cavity. In cases of hospital gangrene of the extremities, and in cases of gangrene of the intestines, heart clots and fibrous coagulations were universally present. The presence of those clots in the cases of hospital gangrene, while they were absent in the cases in which there was no inflammatory symptoms, sustains the conclusion that hospital gangrene is a species of inflammation, imperfect and irregular though it may be in its progress, in which the fibrous element and coagulation of the blood are increased, even in those who are suffering from such a condition of the blood, and from such diseases as are naturally accompanied with a decrease in the fibrous constituent.