(1) The unusual organism previously described (1929) has since been recovered from two additional sources, in each case children suffering from dysenteric symptoms.
(2) It is suggested that this organism be named the “Newcastle dysentery bacillus.”
(3) A more extensive study of its biochemical reactions, using Lemco broth (Dudgeon and Pulvertaft, 1927), as a basis for carbohydrates, has shown that these reactions are notably free from variation and that they exhibit decided divergences from those characteristic of certain bacilli often associated with, but not specifically related to, dysentery. They are more or less closely paralleled in the case of the Glässer-Voldagsen sub-group of the Salmonella, and particularly the Dammann strain of Voldagsen's bacillus, but nevertheless show quite definite differences.
(4) Further examination of the serological peculiarities of the Newcastle bacillus has demonstrated that it is difficult to prepare from it a very active rabbit anti-serum, that its velocity of agglutination is low, and that the titre obtained with saline suspensions is higher than that obtained with broth cultures.
(5) Complete absence of agglutination has been the result in tests with B. typhosus, many members of the Salmonella group, including all most frequently met with and also the Glässer-Voldagsen sub-group, and with a number of the bacilli often associated with, but not specifically related to, dysentery. On the other hand, with one strain of B. dysenteriae Sonne (3) there was a suggestion of agglutination and with at least four out of five races (V, W, X, Y and Z) of B. dysenteriae Flexner this was well-marked.
(6) Saturation with a mixed suspension of these five races completely removes all trace of these secondary agglutinins without materially affecting the specific agglutinins for the Newcastle bacillus while, on the other hand, saturation with each of the four strains of the latter has, in each separate instance, practically eliminated the specific and completely removed the secondary agglutinins.
Finally we desire to acknowledge the helpful criticism we have received from Prof. H. J. Hutchens throughout our study of this organism, the facilities placed at our disposal by Dr Harold Kerr, Medical Officer of Health for Newcastle, and the great assistance rendered by the Deputy Medical Officer of Health, Dr J. A. Charles.