Which preposition to use with biz

as Occurrences 1%

Mrs. GREEN, the mother of my dorters, is a woman who understands her biz as housekeeper, and anybody who gits one of her gals won't be troubled to death by keepin' a cook to boss 'em around.

in Occurrences 1%

TORTONI'S is all very spiffing, the Bullyvard life is A 1, And the smart little journals of Parry, though tea-paper rags, is good fun; But a Briton abroad is a Briton; chic, spice, azure pictures, rum crimes, Is all very good biz in their way, but they do not make up for our Times!

Which preposition to use with  biz