He and the Old Doctor would have been great friends had they ever met. Murphy, whom I considered a most wonderful surgeon, and whose skill I never hope to approach, stated to me many times while a student that he lost more cases from post-operative pneumonia than any other condition and that in upper abdominal conditions like gall bladder, stomach, and similar operations, post-operative pneumonia constituted the most of his mortality. This great man was afraid of post-operative pneumonia, while I, a much less skilled surgeon, am no more afraid of post-operative pneumonia than I am of something occurring in a distant state because with osteopathic treatment, we have eliminated post-operative pneumonia as a fatal condition. PART SECOND INFECTIOUS DISEASES Fever =Fever= is due to various causes, so that a definite statement cannot always be given as to the cause of fever in every disease. Each fever case, like all other disorders, is a law unto itself; different causes are found in different cases. Moreover, often only theories, and not absolute facts, can be given. Fever may be present when a local disease assumes a constitutional character or when the constitutional character is manifested from the beginning of the disease. Fever may be a systemic disorder or a symptom of disease, and is characterized by an increase of body temperature. Other symptoms are usually present, as an accelerated pulse, disturbances of distribution of the blood, increased catabolism, and disordered secretions. =Etiology.=—In infectious diseases fever is due chiefly to the action of various toxic or harmful agents, produced by the disease, upon the fluids of the body and upon the nervous system. Disturbances of the thermogenic centers and nerves of the brain or cord by harmful agents, or by lesions of the anatomical structures affecting these nerves, are sources of fever. Also disturbances of the vasomotor centers (in the medulla and auxiliary centers along the cord) and nerves are causes of fever in many instances. A disturbed or lessened function of the nerves controlling sweating is an important factor. The multiplication of micro-organisms in the body, acting directly on the tissues or by producing toxic substances which affect the nervous system, is a fruitful source of fever. A few cases may be caused by direct affection of the nervous system, as is shown by appearance of fever in epileptic attacks, or by the passage of a catheter into the bladder. In a large number of all cases a demonstrable cause can be found upon careful examination, whether the fever be due to a necrosed mass of tissue, the introduction into the system of decomposed food, infectious diseases, a lesion of some anatomical structure affecting a thermogenic, vasomotor or sweat center, a lesion to the innervation to the heart (vagi and cervical sympathetic) causing a rapid heart, or a lesion to the lymphatic system.