_Author_: Hamdi. _Title_: Results of Immunization Tests against Typhus. _Quotation_: Journal for Hygiene 1916, 82. Quoted in Kolle-Kraus-Uhlenhut, Manual of Pathogenic Micro-organisms VIII/2, 1204 (1930). _Purpose_: See title. _Experiment_: “By means of virulent blood of patients, Hamdi was in a position to check on a large number of persons who had been treated before partly with the blood of patients (80), partly with the blood of reconvalescents (54), partly with a mixture of both blood types (19) * * *. Upon the infection with the blood of patients, none of the thrice protectively vaccinated persons became ill, two out of seven persons who had been protectively vaccinated only twice became ill.” _Experimental persons_: “In the first place, these experiments concerned persons who had been sentenced to death for crimes,” “* * * large number * * *.” _Result_: Effectiveness of protective vaccination was proved. _Excerpt from Original Report No. 26_ _Author_: Doerr, R. _Title_: Pappataci Fever and Dengue. _Quotation_: Kolle-Kraus-Uhlenhut, Manual of Pathogenic Micro-organisms VIII/1, 501 et seq. (1930). _Purpose_: Research in Etiology and Transmission of Pappataci Fever. _Experiment_: II. Pappataci Fever. Page 508: “The organism circulates in the blood of the patients during the first 24 hours after the beginning of the fever. Its presence is betrayed only from the pathogenicity (infectivity) of the blood for healthy and receptive (not immune) human beings. If such an individual were to be injected with the blood of a subcutaneously feverish person he would fall ill * * * of a fever attack typical in every respect. This experiment was at first successfully performed by Doerr (1908), later by Doerr and Russ in the Hercegovina, by Birt in Malta, by Tedeschi and Napolitani in Italy, by Lepine (Three Days Fever in Syria, Bull. Soc. path. exot. _20_, 251, 1927) in Syria. The experiment was repeated by Kligler and Ashner in Palestine and furnished positive results in about 35 single experiments. In this connection it must be considered that, almost without exception, the inoculated persons lived in areas free from epidemics and phlebotomus so that an accidental natural infection was out of the question from the beginning.” Page 513: “But Whittingham and Rook brought infected phlebotomus from Malta to England. They succeeded in breeding imagines from the eggs of flies laid in England and infecting human beings by the bites of these flies, that is producing fever attacks. In this way, the question of where the virus of the Pappataci fever remains over the winter would apparently be answered.” _Experimental persons_: About 35. _Result_: Determination and confirmation of the etiology and the method of transmission. _Report After the Original No. 33_