400 PA THOGENIC BA CTERIA. from a recent autopsy are not pathogenic in moderate amounts for rabbits or guinea-pigs. Liver-tissue pre- served at 28° F. in an antiseptic wrapper is very patho- genic for guinea-pigs when injected subcutaneously, but Sternberg found that this pathogenesis was not true of yellow fever livers only, as it developed also in control- autopsies. Extended research of the alimentary canal in yellow fever showed the intestine to contain a great number of bacteria, but no pure or nearly pure culture of any single species, as in cholera. Few liquefying bacteria were found, and the most abundant bacterium was, as in health, the Bacterium coli communis. The most important micro-organism met with was Bacillus x (Sternberg), which was isolated by the culture- method from a considerable number of cases, and may have been present in all. It was not present in any of the control-experiments. It was very pathogenic for rab- bits when injected into the abdominal cavity. Sternberg- says: "It is possible that this bacillus is concerned in the etiology of yellow fever, but no satisfactory evidence that this is the case has been obtained by experiments upon the lower animals, and it has not been found in such numbers as to warrant the inference that it is the veri- table infectious agent." The latest researches upon yellow fever are those of Sanarelli.1 In studying the cadavers of yellow fever San- arelli found them either entirely sterile or universally invaded by certain microbic species, such as the Strepto- coccus pyogenes, the colon bacillus, the protei, etc., which cannot be the cause of the disease. In the second case he examined he was fortunate enough to find what he is satisfied is the specific microbe, the Bacillus icter- oides. In ii autopsies he never found the organism alone, but always associated with the ordinary bacteria mentioned above. The Bacillus icteroides must be sought for in the blood and tissues, and not in the gastro-intes- 1 Brit. Med. Journ., July 3, 1697.