But there is one situation in which goods introduced into one State from another have until recent years enjoyed a special immunity from taxation by the former, and that is when they were introduced in consequence of a contract of sale. The leading case is Robbins _v._ Shelby County Taxing District,[581] in which the Court, after a penetrating survey of commercial practices, ruled that "the negotiation of sales of goods"--in this instance by sample--"which are in another State, for the purpose of introducing them into the State in which the negotiation is made, is interstate commerce." In short, whereas in foreign commerce, importation is succeeded by the right to sell in the original package, in interstate commerce sale was succeeded by the right of importation, which continued until the goods reached the hands of the purchaser. The benefits of this holding were extended in a series of rulings in which it was held to apply whether solicitation of orders was or was not made with sample,[582] and to sales which were not, accurately speaking, consummated until the actual delivery of the goods, which was attended by local incidents. So, where a North Carolina agent of a Chicago firm took orders for framed pictures, which were then sent to him packed separately from the frames and then framed by him before delivery, the rule laid down in the Robbins case was held to apply throughout, with the result that North Carolina could tax or license no part of the transaction described;[583] so also as to a sewing machine ordered by a customer in North Carolina and sent to her C.O.D.;[584] so also as to brooms sent in quantity for the fulfillment of a number of orders, and subject to rejection by the purchaser if deemed by him not up to sample.[585] Said Justice Holmes in the case last referred to: "'Commerce among the States' is a practical conception not drawn from the 'witty diversities' * * * of the law of sales. * * * The brooms were specifically appropriated to specific contracts, in a practical, if not in a technical, sense. Under such circumstances it is plain that, wherever might have been the title, the transport of the brooms for the purpose of fulfilling the contracts was protected commerce."[586] Nor did it make any difference that the solicitor received his compensation in form of down payment by the purchaser.[587] Moreover, sales under a mail order business, with delivery taking place within the State to a carrier for through shipment to another State to fill orders, was held to be beyond the taxing power of the first State.[588] The fact that a concern doing a strictly interstate business had goods on hand within the State which were capable of being used in intrastate commerce, did not, the Court declared, take the business out of the protection of the commerce clause and allow the State to impose a privilege tax on such concern. LIMITATION OF THE ROBBINS CASE