Ritchie has recently tested the sera of 792 normal persons and found that 30% of these individuals agglutinated Shiga bacilli in 1 to 32, while with Flexner strains 41% agglutinated in 1 to 64 and 30% in 1 to 128. For comparison Ritchie’s results with typhoid showed that only 6% agglutinated such bacilli in 1 to 16. There is some evidence that typhoid vaccination increases the agglutinating power of the serum against dysentery organisms. These findings are remarkable, as the usual advice is to consider an agglutination of 1 to 30 as fairly specific for Shiga infections and 1 to 100 for Flexner ones. Willmore and Savage tried heating serum to 56°C. for thirty minutes, but found that such a procedure was of no practical value with dysentery, thus differing from Malta fever serum where such a procedure is of value in destroying coagglutinins and thus increasing the specific action. The work of Ohno would indicate that we should trust to the acid-producing effect on mannite for differentiating Flexner and Shiga strains rather than on agglutination because it was found that agglutinins for an acid strain were not always more specific for such strains than for nonacid ones. At the same time it is the rule for a Flexner type bacillus to show specificity for its serum and the Shiga type for the serum of the more toxic, nonacid-fast Shiga strain cases. The statement of Willmore and Savage that the differentiation of bacillary dysentery infections is a refinement of technique seems a proper view because with a polyvalent serum for treatment one only needs to know that the case is one of bacillary dysentery for proper treatment. Of course with a monovalent serum, effective only for the Shiga bacillus, one would have to determine whether the organism producing the dysentery was of that strain. As a matter of fact it takes considerable time and laboratory skill to carry out reliable cultural and serological tests. From a practical standpoint we can use the therapeutic polyvalent serum for agglutination and any organism recovered on the plate made from the faeces which agglutinates in 1 to 50 or 1 to 100 may be considered as diagnostic of bacillary as against amoebic dysentery. Often one does not see a case of dysentery until late in the disease and then, provided the condition is serious and the diagnosis points to a bacillary infection it would be better to inject the curative serum rather than await laboratory confirmation. PROPHYLAXIS AND TREATMENT =Prophylaxis.=—The ease with which water-closet seats may be contaminated should make us pay great attention to their disinfection during an outbreak of bacillary dysentery. The same applies to the bedclothes of such patients sent out for laundering.