SELECTED PAPERS 



life, is exclusively the result of the continuous vigilance of the mutually 

 cooperating health services in the various countries. This international 

 cooperation has found its highest expression in the 'World Health Or- 

 ganization', established by the United Nations in 1946 in continuance 

 of a similar activity of the League of Nations. Especially because 

 present-day man has thus been lulled into sleep with respect to the 

 dangers of infectious diseases it does not seem superfluous to review 

 some examples of the pestilences that have seriously threatened the 

 perpetuation of mankind in the course of time. 



In the first place I refer to the succession of bubonic plague epidem- 

 ics that ravaged Europe and the other parts of the known world during 

 the fourteenth century. In F. Eberson's book, 'The Microbe's Chal- 

 lenge', we find the estimate that 25 million persons died of this disease 

 in Europe alone, and around 60 million in all; this amounts to approx- 

 imately one quarter of the entire human population at that time. An 

 excellent description of the symptoms of the disease, which unambigu- 

 ously points to the diagnosis of bubonic plague, we owe to Boccaccio 

 who fled before an outbreak in 1348, and chose voluntary exile in 

 Florence where he wrote his 'Decameron'. At present it may be con- 

 sidered well established that the successive epidemics reached Europe, 

 via the Near East and North Africa, from Asia where the disease is 

 endemic. It is interesting to note that even in those days man made 

 some timid attempts at defense. In various harbour cities the idea 

 gained ground that the disease apparently was introduced by way of 

 ships, and in 1383 Marseille issued a decree by which in case of sus- 

 picion the ship's crew was forced to remain on board for forty days 

 before permission was given to disembark. It is this decree that even 

 nowadays is one of our indispensable defense measures, and although 

 the time span is no longer adhered to, it is responsible for our use of 

 the word 'quarantine'. 



I shall not review the numerous bubonic plague epidemics that 

 scourged Europe in later centuries, though in passing I wish to mention 

 the epidemic of 1663- 1668 that also affected our country. In 1663 the 

 number of deaths from the plague in Amsterdam alone amounted to 

 10,000 out of a total population of 200,000; during the next year the 

 number even increased to 24,000. 



Not until 1894 did Kitasato and Yersin independently show that 

 bubonic plague is caused by a bacterium, now designated as Pasteur- 



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