Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 160, § 212

A railroad corporation shall not receive, forward or deliver milk in large quantities over any portion of its line, or permit others so to do, under contract, lease or hiring of cars or otherwise, without at the same time providing, as regards time, care and preservation of the milk and the return of the empty cans, equal facilities and advantages for receiving, forwarding and delivering milk by the can over the same portion of its line; nor without establishing a tariff for the milk by the can which is the same rate which it charges or receives as aforesaid for milk in large quantities.