=Diminution of the respiratory murmur=, like its =increase=, may be =partial= or =general=. =General diminution= is seen in anæmia, in low fevers, in all very prostrate conditions from the mere want of power to dilate the chest; in general emphysema (broken wind, heaves), in general miliary tubercular deposit in the lungs, or in that form in cattle in which the tubercle has been replaced by cretaceous deposits, from the animal’s inability to fully dilate the air cells; in enteritis, peritonitis and metritis the chest is more fully dilated because of the pain attendant on that act, and the breathing being short and quick the murmur is correspondingly low. In certain brain diseases with sluggish respiration the sound is equally feeble. =Partial diminution of murmur= is more surely indicative of lung disease. It may arise from partial congestion when a supplementary murmur will be observable over other parts of the lungs, and a crepitant râle soon appears in the congested part; from local emphysema in which there is increased resonance in percussing the part; from tubercular or cretaceous deposit, when there will be exaggerated murmur elsewhere, or from bronchitis with blocking up of one or more small bronchial tubes and with louder respiratory sound in other parts. =Absence of respiratory murmur= may be due to various causes, all of a diseased nature. Hepatisation of lung may be recognized when this condition is found associated with a crepitating râle around the margin of the silent part, and when percussion shows its solidity and want of resonance. Splenisation is associated with absence of respiratory sound and dullness on percussion, but no surrounding crepitation. Absence of sound in water in the chest is confined to the lower part of the chest, keeps the same level and ratio of increase in front and behind, and in the horse on the two sides, and has been preceded by the characteristic catching breathing and the friction sounds of pleurisy. Large tumors and extensive and circumscribed tubercular deposit will give rise to absence of sound over a limited area and plugging up of one or more bronchial tubes will lead to a similar result. Hepatisation of lung and water in the chest are, however, the common causes of loss of respiratory murmur. The =bronchial or tubal sound= may be increased in pitch and in harshness in two conditions. 1st. In the early stages of bronchitis when the lining mucous membrane of the air passages is dry, thickened and inelastic. 2d. When that portion of lung intervening between one of the larger tubes and the surface of the chest is solid (hepatised) and thus proves a better conductor of sound than in the normal condition.