This document consists of a list of establishments holding licenses issued in accordance with Section 351 of the Public Health Service Act, and a list of products which each establishment is licensed to manufacture. Section 351 regulates the sale, barter, and exchange of viruses, serums, toxins, antitoxins, analogous products, and arsphenamine or its derivatives (or any other trivalent organic arsenic compound). Licensed establishments are inspected regularly to ensure technical competence of personnel, sanitary conditions of the premises, proper manufacturing methods, and safety, purity, and potency of the licensed products. Establishments are arranged by license number showing the products for which each is licensed. A list of biologic products also provided with license numbers of the establishment licensed for each product.