For a quarter of a century, investigators of infectious disease have pointed with pride to the therapeutic miracle of antitoxin for diphtheria, this major pestilence of the nineteenth century having apparently been conquered for all races and for all time. Nevertheless, diphtheria has reasserted its ancient mortality rate in parts of Europe, within the last three years. Some pessimism and theoretical perplexity followed this suddenly acquired clinical intractability. Renewed optimism, however, is inspired by the recent discovery by Anderson and his co-workers1 of Leeds, England, that the apparent intractability may be due to the introduction or local evolution of a hitherto unknown bacterial form, for which they propose the name B. diphtheriae gravis.
The first indication that the usual serum therapy was not successful in modern diphtheria was the steady rise in case mortality in the Virchow Krankenhaus, Berlin. From a 5 per cent case mortality in 1924, the