Much controversy has been occasioned by the claim of Sanarelli and others that the bacillus icteroides is the causative agent of yellow fever. Surgeon-General Sternberg has persistently opposed Sanarelli's claims. Reference to this controversy has been made in these columns from time to time.1 Reed and Carroll, of the U. S. Army, came to the conclusion that the bacillus icteroides is a variety of the bacillus of hog cholera. The commission of medical officers, United States Marine-Hospital Service, which studied yellow fever in Havana and elsewhere, reported favorably to Sanarelli, having succeeded in isolating the bacillus icteroides from all the cases of yellow fever studied in Havana. This commission also claimed to have discovered the manner of primary infection, namely, through the respiratory tract, but this claim did not meet with general favor among bacteriologists, as the evidence presented hardly seemed sufficient to justify the statements of the commission.