Abstract

Within recent years attempts have been made to determine whether microor-ganisms have the capacity of producing substances active against animal viruses in a manner comparable to the production of antibiotics or antibacterial agents (Jones et al., 1945; Robinson, 1943). In this work the lack of techniques an-alogous to those commonly used for the study of antibiotics necessitated a more or less random choice of cultures. Needless to say, this indiscriminate testing would appear to be relatively inefficient as contrasted with the use of selective procedures such as those which have proved helpful in antibiotic work. In view of the increasing interest in the possibilities of an approach to the virus problem through studies of microbial antagonisms and the production of specific anti-viral agents, attempts have been made to modify certain methods for investigat-ing agents active against bacterial viruses or bacteriophages. The practicability of utilizing bacteriophages as test agents in the search for chemotherapeutic substances active upon true viruses may be questionable in view of the marked differences between the bacteriophages and viruses, and