The discovery of the hemophilic character of B. influenzæ has been confirmed by a long list of investigators. The agar smeared with pigeon blood as used by Pfeiffer has not, however, been found fully satisfactory and many modifications have been made. The fact that hemoglobin in some form is necessary for the growth of these bacteria has led to a great deal of study in attempts to discover the chemical part, or parts, essential for this purpose. Hemoglobin in very small amount, as shown by Davis and others, is sufficient to make media suitable for growing B. influenzæ. This fact has led to much confusion, owing to the difficulty of eliminating all possible sources from which some form of hemoglobin might enter the media. Kitasato used a glycerin agar and succeeded in growing the influenza bacillus for 10 transfers. Pielicke, however, did not consider that Kitasato was actually dealing with the influenza bacillus, but that he as well as Babes, Bruschettini and Markel had most probably streptococci in their cultures. Besson held the same view of Kitasato’s organism. It would further appear from the illustrations of Klein that he also grew streptococci and not the B. influenzæ. The first culture of the influenza bacillus was probably obtained by Bujiwid in February, 1890. He grew on agar smeared with the spleen pulp of an influenzal patient a tiny bacillus which he was unable to grow on blood free medium, but he did not appreciate its importance until Pfeiffer’s article appeared. Teissier in his book on “L’ Influenza en Russie” mentioned this culture.