The gas-producing bacilli, now commonly spoken of as B. welchii, occur in a variety of lesions, but their chief hold on our interest lies in their connection with gas gangrene, that dreadful complication of wounds, especially those received in modern warfare. The effects of gas bacilli have been explained in various ways, most often as due to some form of intoxication, either from the products of the decomposition of infected tissues or through the generation of fatty acids as well as in other ways, but it has not been thought that the effects were dependent on true bacterial toxins. Bull and Pritchett,6 however, report highly interesting experiments, the results of which indicate that, under suitable conditions, cultures of gas bacilli produce true toxins to which their pathogenic effects, at least in certain animals, may be ascribed. There are produced at least two distinct toxins, one of which is hemolytic