Consciously or unconsciously, health can be transmitted. A very strong man, living with a weak man, will make him a little stronger, whether he knows it or not.
There is a wisdom in this beyond the rules of physic: a man's own observation what he finds good of and what he finds hurt of is the best physic to preserve health.
Man does not live by soap alone; and hygiene, or even health, is not much good unless you can take a healthy view of it or, better still, feel a healthy indifference to it.
The greatest mistake in the treatment of diseases is that there are physicians for the body and physicians for the soul, although the two cannot be separated.