From time to time, over a period of many years, we have recovered from the feces of infants and children, from fecallycontaminated surgical wounds, from a decubitus ulcer, and from post-mortem cultures from the heart blood, peritoneal and pleural fluids in adults, a species of anaerobic bacillus whose close resemblance to the "Kopfchenbacterien" or Escherich was finally pointed out by Hall and O'Toole (1935) and whose identity with the Bacillus paraputrificus of Bienstock was shown by Hall and Snyder (1934).In 1934, Kleinschmidt of Cologne, Germany, reported an anaerobic bacillus occurring in the stools of infants at periods of malnutrition, which in his opinion differed from previously described bacteria and which he called "Bacillus innutritus."The description of "B. innutritus" was at once suggestive of B. paraputrificus, and it so happened that the senior author was able personally to visit Dr. Kleinschmidt in the Kinderklinik der Stadtische Krankenanstalt Lindenborg and to secure two strains of "B. innutritus" for comparison. These were numbered 9340 and 9341 in our series and compared morphologically and culturally with our strains 4042Ea and 4453 of B. paraputrifiCus, isolated by Miss O'Toole from the stools of three-and four-day old infants in 1930.It is unnecessary to repeat all of the details of our findings which showed definitely that all of these strains belonged to the species, Bacillus paraputrificus, as described by Hall and Snyder. 631 on July 31, 2020 by guest