The _physical signs_ of lung disease vary. If pneumonia is present it is betrayed by its characteristic symptoms. In the absence of inflammation there is dullness on percussion over the affected area, and on auscultation an absence of the respiratory murmur, and perhaps abnormal clearness of bronchial, cardiac and other sounds from deeper parts. It differs from pneumonia in the absence of fever and of any crepitation surrounding the consolidated portion. The expectoration is serous or watery, rather than rusty or purulent. The _prognosis_ is always grave in proportion to the incurable nature of the primary disease. Chronic valvular or Bright’s disease, miliary tuberculosis or malignant tumors would render the case hopeless, while in acute pneumonia, or nephritis or parasitism there may be some hope. The _treatment_ will largely consist in the therapeutics of the primary disease, yet we may also seek to relieve the dangerous symptoms of œdema. The frequent change of position may serve to limit hypostatic accumulation. Diuretics or purgatives in strong patients will favor absorption. Pilocarpin more than any other agent secures temporary absorption but cannot be continued owing to its depressing effects. Digitalis is often valuable in improving the heart’s action, and acting freely on the kidneys. Dry capping on the chest acts as a derivative. ATELECTASIS. COLLAPSE OF LUNG. Atelectasis in bronchitis, congenital, etc. Airless condition in the absence of exudation. Causes, congenital persistence in butcher animals. Blocking of air tubes by exudate—ball valve. Desquamation of ciliated epithelium. Compression by hydrothorax, pneumothorax, and false membrane. Symptoms. Percussion flatness, juvenile respiration elsewhere, blowing sounds loud. Drum-like sounds on emphysema and pneumothorax. Cyanosis. Lesions, depressed, flesh-like, non-crepitating lobules or lobuletes, sink in water, dilatable. Treatment, rouse respiratory centres, douches, cold and warm, slapping, electricity, forced inspiration, diet, massage. Treat attendant disease. This has been already referred to as a result of bronchitis, but it deserves special mention as a sequel of that affection, and in various domestic animals, as an independent condition. The condition is one of consolidation of lung by the complete exclusion of air, but without any infiltration of its substance by inflammatory exudate or dropsical effusion. The tissue remains in its normal state apart from the fact that its bronchioles and air sacs are undilated. The affected portion has a solid dark fleshy appearance. The collapsed portion often represents one lobule or group of lobules which communicate with a single bronchium.