First. That the microörganism discovered by Professor Giuseppi Sanarelli, of the University of Bologna, Italy, and by him named “bacillus icteroides” is the cause of yellow fever. Second. That yellow fever is naturally infectious to certain animals, the degree varying with the species; that in some of the rodents local infection is very quickly followed by blood infection, and that, while in dogs and rabbits there is no evidence of this subsequent invasion of the blood, monkeys react to the infection the same as man. Third. That infection takes place by way of the respiratory tract, the primary colonization in this tract giving rise to the earlier manifestations of the disease. Fourth. That in many cases, probably a majority, the primary infection, or colonization, in the lungs is followed by a “secondary infection,” or a secondary colonization in the blood of the patient. This secondary infection may be complicated by the coinstantaneous passage of other organisms into the blood, or this complication may arise during the last hours of life. Fifth. There is no evidence to support the theory advanced by Professor Sanarelli that this disease is primarily a septicemia, inasmuch as cases do occur in which the bacillus icteroides cannot be found in the blood, or organs in which it might be deposited therefrom. Sixth. That there exists no casual relationship between the bacillus X of Sternberg and this highly infectious disease; and that this bacillus X is frequently found in the intestinal contents of normal animals and of man, as well as in the urine and the bronchial secretion. Seventh. That, so far as your Commission is aware, the bacillus icteroides has never been found in any body other than of one infected with yellow fever; and that whatever may be the cultural similarities between this and other microörganisms, it is characterized by a specificity which is distinctive. Eighth. That the bacillus icteroides is very susceptible to the influences injurious to bacterial life, and that its ready control by the processes of disinfection, chemical and mechanical, is assured. Ninth. That the bacillus icteroides produces in vitro as well as in vita a train of the most marked potency; and that, from our present knowledge, there exists a reasonable possibility of the ultimate production of an antiserum more potent than that of Professor Sanarelli.