Scientists at Bristol University in UK have discovered that a certain type of bacteria in mud makes humans happy, restores immune functions, alleviates depression etc. Even treats cancer. Hey, they could have just checked with Dennis the Menace or Calvin about the joys of rolling in the mud. Or read Gandhi and Tagore. Here is one of his poems titled;
CHILD, how happy you are sitting in the dust, playing with a broken twig all the morning.
I smile at your play with that little bit of a broken twig.
I am busy with my accounts, adding up figures by the hour.
Perhaps you glance at me and think, "What a stupid game to spoil your morning with!"
Child, I have forgotten the art of being absorbed in sticks and mud-pies.
I seek out costly playthings, and gather lumps of gold and silver.
With whatever you find you create your glad games, I spend both my time and my strength over things I never can obtain.
In my frail canoe I struggle to cross the sea of desire, and forget that I too am playing a game.
From:The Crescent Moon by Rabindranath Tagore (1913)
Nature poets and other essayists always spoke on the joys of gardening, working with soil and such things. Play in the mud, Mud baths, Mud packs, Mud Poultices...
Of course, Mud is medicinal, Mud is merry.