Put tripe, marrow bone and stock into pot and cover.
Simmer for 2 hours.
Add onion, carrots and celery.
When mixture simmers again, slowly add rice and stir.
Add soy grits, salt and yeast and cover again.
Continue simmering until rice is tender; remove from heat.
Take out marrow bone.
Gradually blend in egg yolk.
Just before serving, add lemon juice.