But this is not often the case.

An illness, even though it be treated as subordinate, must be respected more or less according to its nature.

But when that is done normally no bad habits will be left behind.
I know a young girl who was ill with strained nerves that showed themselves in weak eyes and a contracted stomach.

She is well now--entirely well--but whenever she gets a little tired the old habits of eyes and stomach assert themselves, and she holds firmly on to them, whereas each time of getting overtired might be an opportunity to break up these evil habits by a right amount of rest and a healthy amount of ignoring.
This matter of habit is a very painful thing when it is supported by inherited tendencies.

If a young person overdoes and gets pulled down with fatigue the fatigue expresses itself in the weakest part of his body.