Unnecessary noise, or noise that creates an expectation in the mind, is that which hurts a patient. It is rarely the loudness of the noise, the effect upon the organ of the ear itself, which appears to affect the sick. How well a patient will generally bear, e. g., the putting up of a scaffolding close to the house, when he cannot bear the talking still less the whispering, especially if it be of a familiar voice, outside his door.

There are certain patients, no doubt, especially where there is slight concussion or other disturbance of the brain, who are affected by mere noise. But intermittent noise, or sudden and sharp noise, in these as in all other cases, affects far more than continuous noise—noise with jar far more than noise without. Of one thing you may be certain, that anything which wakes a patient suddenly out of his sleep will invariably put him into a state of greater excitement, do him more serious, aye, and lasting mischief, than any continuous noise, however loud.

Never to allow a patient to be waked, intentionally or accidentally, is a sine qua non of all good nursing. If he is roused out of his first sleep, he is almost certain to have no more sleep. It is a curious but quite intelligible fact that, if a patient is waked after a few hours' instead of a few minutes' sleep, he is much more likely to sleep again. Because pain, like irritability of brain, perpetuates and intensifies itself.