Cream Horseradish Sauce

Chop fine sufficient celery to make a half pint; season it with a quarter
of a teaspoonful of salt, a teaspoonful of onion juice, a dash of pepper.
Rub the spoon with garlic, mix thoroughly, stir into it the yolk of an egg
that has been beaten light with two tablespoonfuls of cream; add a few
drops of lemon juice or tarragon vinegar and serve.