It may happen that in examining a patient pneumonia is diagnosed under circumstances which seem to forbid its being regarded as simple or primary. This may be explained by the fact that ruminants are very apt to suffer from pneumonia produced by foreign bodies. The lung may be penetrated either by some sharp object making its way forwards from the rumen or reticulum or by liquid or solid material passing into the trachea. These are two common methods by which this form of pneumonia is produced. PNEUMONIA DUE TO THE MIGRATION OF FOREIGN BODIES FROM THE RETICULUM. =Causation.= The conditions under which food is swallowed by ruminants after preliminary mastication permit indigestible objects, such as stones, fragments of wood, nails, needles, bits of iron wire, etc., to enter the rumen, whence they reach the reticulum in consequence of peristaltic movements. Sharp, perforating objects, like needles or fragments of iron wire, penetrate the walls of the gastric compartments, and, impelled by the movements of these organs, pass through the intervening tissues, usually in the direction of the heart. Under conditions which cannot precisely be defined, these foreign bodies make their way towards the pleural cavity (usually the right, in consequence of the situation of the reticulum), traverse the diaphragm, and directly penetrate the base of the lung. As the migrating object is usually infected, its passage through the diaphragm always produces a localised patch of diaphragmatic pleurisy. Although possible, it is only rarely that the pleural sac becomes generally infected, or that rapidly fatal septic pleurisy is set up. Usually the localised pleurisy causes the base of the lung to become adherent to the anterior surface of the diaphragm. The foreign body continuing its movements, passes into the lung, and there sets up pneumonia. =Symptoms.= When the practitioner is first consulted he often finds only indications of the crisis period of a localised pneumonia at the base of the affected lung. The symptoms include fever, accelerated breathing, moaning, loss of appetite, cough without discharge, dulness over the base of the lung on percussion, disappearance of the respiratory murmur in the dull area, souffle opposite the inferior bronchi, and normal or juvenile respiration towards the front, _i.e._, in the anterior lobe, and sometimes in the cardiac lobe.