On the nature and cause of the respiratory murmur / by Hyde Salter.

  • Henry Hyde Salter
Date:
1864
Catalogue details

Licence: Public Domain Mark

Credit: On the nature and cause of the respiratory murmur / by Hyde Salter. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    spiration are voluntary muscles. Hence we shall have en- gaged, to accomplish tlie act of breathing, a voluntary and an involuntary power. The function would be easily performed as long as these powers acted in unison. But by varying the rapidity of our breathing, we should soon have two powers opposed to each other—the involuntary muscles acting to close the bronchial tubes, while the voluntary muscles acted to expand them. We should then be able to dilate the chest only when we adjusted the inspiratory movements to the action of the involuntary muscles. But we never perceive any necessity for' such an adjustment. The test which this circum- stance affords us is one of extreme delicacy. For, if the two powers were not exactly in unison, there would occur intervals, like the heats in music, when they would coincide with, or be opposed to, each other. The inspiratory acts would be alter- nately easy and difficult, according as the voluntary and in- voluntary muscles were in the same or opposite phases. But however rapid we make our breathing, we perceive no difference in the ease with which successive acts of inspiration are per- formed. This circumstance is a proof the most decisive, that the fibres of the bronchi have no independent rhythmical motions of contraction. If, then, the bronchi do not contract at each inspiration, their contractions cannot be the cause of the respiratory mur- mur, and Dr. Blackiston's theory is untenable. 4< lonuon: T. RICItARnR, 37 OT. QCEEN STEEET.
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