Compiled from the joint working card catalogue of the Division of Zoology, Bureau of Animal Industry, and of the Division of Zoology, Hygienic Laboratory, U.S. Public Health ad Marine-Hospital Service. It consists of three parts - Authors, Subjects, and Hosts. The Authors Index is published in an edition of 2,568 copies, and not for general free distribution but is intended for use of libraries, educational institutions, experiment staions, laboratories, sanitary officials, and investigators.