When was the "salad bowl" term introduced?

The phrase gained wider currency in 1908 during the great wave of slavic jewish and italian immigration when israel zangwills play ''the melting pot'' was produced.

The salad bowl concept suggests that the integration of the many different cultures of United States residents combine like a salad, as opposed to the more traditional notion of a cultural melting pot. New York City can be considered as being a "salad bowl".