31 Pa. Stat. § 671
Every person, firm, company, association, corporation, or agent thereof, engaged in the business of buying milk or cream on the basis of, or in any manner with reference to, the amount or percentage of butterfat contained therein, as determined by the "Babcock test," shall use standard "Babcock" bottles, pipettes, and weights, as defined in section two of this act. All such Babcock test bottles, pipettes, and weights, so used, shall comply with the act of May 5, 1921 (P.L. 389), having to do with approval of types of weights and measures and weighing and measuring devices as well as all of the other provisions of the said act. It shall be unlawful for any person, persons, firm or company, association, corporation, or any agents, to use any other than standard test bottles, pipettes, and weights, as provided in this section, to determine the amount of fat in milk or cream bought on the butterfat basis as determined by the Babcock test.
31 P.S. § 671