Organisms which appear to be morphologically, culturally, and serologically identical have been recovered in four separate outbreaks of illness suggestive of dysentery.

They have been readily isolated in considerable numbers from all cases examined in the early phase of the attack.

When 1 per cent, peptone water is used as a basis for carbohydrates these organisms usually leave lactose, mannite, dulcite, and saccharose unaffected but ferment glucose and maltose with the production of acid. Barely, a minute amount of gas is also produced from glucose and occasionally slight acid and gas from dulcite. On the other hand, when Lemco broth (Dudgeon and Pulvertaft, 1927) is used as a basis, glucose, dulcite, and maltose are consistently fermented with the production of acid and gas.

Agglutination tests against normal sera and against anti-sera prepared from the dysentery and paradysentery bacilli and from B. paratyphosus A are uniformly negative but strains of the organism derived from all four sources are agglutinated to approximately the same titre by an anti-serum prepared from one of them although this anti-serum has no effect on three organisms whose reactions present some degree of similarity.

The organisms do not appear to be toxic for rabbits.

With all patients affected in these outbreaks, whose blood was available for examination, the serum has shown the presence of specific agglutinins which could not be demonstrated in normal serum.

On the whole, therefore, the evidence suggests that these organisms may be responsible for the diseased condition.