United States v. Bausch & Lomb Optical Co., 321 U.S. 707, 722 (1944), was an action by the United States to restrain alleged violations of 1 and 3 of the Sherman Act. The Court held that a distributor, Soft-Lite Lens Company, Inc., violated the Sherman Act when, as was the case with Parke Davis, the refusal to sell to wholesalers was not used simply to induce acquiescence of the wholesalers in the distributor's published resale price list; the wholesalers "accepted Soft-Lite's proffer of a plan of distribution by cooperating in prices, limitation of sales to and approval of retail licensees. That is sufficient. . . . Whether this conspiracy and combination was achieved by agreement or by acquiescence of the wholesalers coupled with assistance in effectuating its purpose is immaterial." 321 U.S., at 723. In Bausch & Lomb, the District Court had found that Soft-Lite had entered into "agreements with wholesale customers" to fix prices and boycott unlicensed retailers. 321 U.S., at 717. The Court held that the facts "all amply support indeed require, the inference of the trial court that a conspiracy to maintain prices down the distribution system existed between the wholesalers and Soft-Lite." Id., 720. The Court reiterated that resale price maintenance could not be achieved "by agreement, express or implied." Id., 721. In rejecting the applicability of the Colgate doctrine (United States v. Colgate & Co., 250 U.S. 300 (1919)), it said that none of the cases applying the doctrine "involve, as the present case does, an agreement between the seller and purchaser to maintain resale prices." Ibid. It justified the finding of concerted action on the ground that "the wholesalers accepted Soft-Lite's proffer of a plan of distribution by cooperating in prices, limitation of sales to and approval of retail licensees." Id., 723.