YELLO W FE VER. 40^ yellow fever. This fact is not only striking evidence in favor of the specific nature of the Bacillus icteroides, but it places the etiological and pathologic conception of yel- low fever on an altogether new basis.'' The discovery of the Bacillus icteroides, and especially of its toxin, entirely changes our view of the pathology of the disease. Instead of being a disease of the gastro- intestinal tract, as one would conclude from the symp- toms, " all the symptomatic phenomena, all the functional alterations, all the anatomical lesions of yellow fever, are only the consequence of an eminently steatogenous, emetic, and hemolytic action of the toxic substances manufactured by the Bacillus icteroides.7' The mode by which the Bacillus icteroides enters the body to produce the disease has not been made out. The digestive and respiratory tracts are the most likely routes. Sanarelli points out that when it happens that a mould develops ne2r the Bacillus icteroides, the products of material exchange of this hyphomycete or the transfor- mation effected by it, are sufficient to nourish the ba- cillus and enable it to live and multiply, whereas it would be otherwise condemned to a more or less early death. There seems to be no particular mould possessed of this power, as of six experimented upon all were capable of it. Sanarelli is of the opinion that in the holds of ships and in damp places generally the presence of moulds favors the development of the Bacillus icteroides. About the same time that Sanarelli published his researches, Havelburg announced1 the discovery of an entirely different bacillus. Without entering into a long description of Havelburg's bacillus, which seems to be far less established in its specificity, the following are the chief characteristic and differential points: The bacillus is found in the stomach and intestine and in the "black vomit" It is almost the sole orgaii- 1 Ann. de VInst. Pasteur, 1897.