“ But there the carriers relied for defense upon a clause in the second bill of lading, which was not contained in the first. We held that the second bill of lading was void, since under the Carmack Amendment the several carriers must be treated, not as independent contracting parties, but as one system; and that the connecting lines become in effect mere agents whose duty it is to forward the goods under the terms of the contract made by their principal, the initial carrier, and that they are prevented by law from varying the terms of that contract. ”

“ There one of the same railroads had, as connecting carrier, issued a second bill of lading to shippers of live stock, who had received from the initial carriers a through bill of lading on an interstate shipment. ”

“ Most of the matter which was included in it at the instance of petitioners, was clearly not required for a proper presentation of the questions submitted here. Much useless expense has been incurred; and both court and counsel have been subjected to the burden of examining much that is irrelevant. ”