The recently reported discovery by Avery and Dubos4 of the Rockefeller Institute of a highly specialized bacterial enzyme capable of decapsulating type 3 pneumococci both in vitro and in the animal body, and of protecting mice against a thousand lethal doses of type 3 infection, has led to renewed hope that in time bacterial enzymes may be successfully used in clinical therapy. The profession, however, must guard against premature optimism and premature exploitation of such enzymes. Many enzymes are known to be extremely toxic for laboratory animals, intravenous injection of urease, for example, leading to death in from two to three minutes with symptoms resembling those of cyanide poisoning. Clinical trial must be preceded by evidence of nontoxicity or the development of methods that will inhibit or neutralize such toxicity without destroying possible therapeutic value.
The clinical use of bacterial enzymes was suggested about thirty years ago by Emmerich