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.
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.
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.