Before considering various methods of breathing it should be said that, irrespective of these, air should, whenever it is possible to do so, be taken into the lungs through the nostrils and not through the mouth. True, there are times in singing when breath has to be taken so rapidly that mouth-breathing is a necessity, as otherwise the inspiration would not be rapid enough. But to inspire through the nostrils, whenever feasible, is a law not alone for the singer, but a fundamental law of health. In the passage from the mouth to the lungs there is no provision for sifting the air, for freeing it from foreign matter, or for warming it if it is too cold; whereas the nostrils appear to have been designed for this very purpose. Their narrow and winding channels are covered with bristly hairs which filter or sift and arrest the dust and other impurities in the air; and in the channels of the nostrils and back of them the air is warmed or sufficiently tempered before it reaches the lungs. Moreover it can be felt that the lungs fill more readily when air is taken in through the nostrils than when inspiration takes place through the mouth. That breath should be taken in through the nostrils is, like all rules in the correct physiology of voice-production, deduced from incontrovertible physical facts. It is, moreover, preventive of many affections of the lungs, bronchial tubes and throat. Three methods of breathing usually are recognized in books on singing--but there should be only one. For only one method is correct and that really is a combination of the three. These three are called, respectively, clavicular, abdominal or diaphragmatic, and costal; clavicular, because it employs a forced movement of the clavicle or collar-bone accompanied by a perceptible raising of the shoulder-blades; abdominal or diaphragmatic, because breathing by this method involves an effort of the diaphragm and of the abdominal muscles; and costal, which consists of an elastic expansion and gentle contraction of the ribs, the term "costal" signifying "pertaining to the ribs."