Pneumonia lacks a great deal of being a self limited disease. The number of cases with beginning symptoms that fail to develop is too great to be ascribed to coincidence. Of course I know that some of these might have been only pleuritis, some only neuritis, etc. However, in giving the statistics of pneumonia cures we will give only those in which pneumonia developed and showed a hardening or consolidation of the lung tissue. In these cases there can be no argument as to whether there was pneumonia. When we have an acute condition associated with the symptoms of consolidation, we can hardly be confused as to the diagnosis. We may make a mistake in our physical findings, but hardly after a little experience, and certainly when we are sure of the physical findings there will be no trouble in naming the disease. =The Clinical Findings.=—Post-operative pneumonia is a little different from the common pneumonia. It always comes on a little more insidiously. One has to watch for post-operative pneumonia more closely than he would for the attack that we may meet in ordinary practice. A patient may have considerable pain from his wound, may have some pain in the back from the position he is in; there may be headache, and an upset feeling from ether; and the pain comes in the chest. All these symptoms are forerunners of pneumonia, but the pain in the chest is not noticed until it gets quite severe. In other words, there are other things to annoy the patient as well as the attendant, and at first, this condition does not cause complaint. A strong and healthy individual who feels a pain in his pleura, which is the forerunner of pneumonia, knows it at once, because that is the only distress he has. His entire attention is attracted and he asks for a physician’s help. But in the post-operative case, the physician has to keep a look out in order to prevent a case from getting well under way before it is recognized. As an example of this I had a case of a man who was with a party driving an automobile and they tried to cross the railroad track in front of a train. This patient I speak of was one of the survivors. He had a fracture of the femur, fracture of the skull, fracture of three ribs, and otherwise more or less bruised up. Naturally the preliminary work consisted in getting the ribs and legs attended to as well as possible and looking out for cerebral hemorrhage or meningitis.