86 THE FLEA [OH. 



Jehangir in his diary of the plague at Agra (1618) 

 mentions the unusual mortality of the rats. In India 

 it seems long to have been a custom, dictated by 

 experience and caution, to leave houses when rats 

 began to die. In Europe, during the middle ages, 

 the mortality of rats when the plague was raging 

 does not seem to have impressed the chroniclers 

 and during the recent outbreak at Glasgow (1900) 

 none was detected. 



As an illness of mankind, the plague reached 

 Europe from the East. We have no evidence of any 

 outbreak in Europe before the reign of the Emperor 

 Justinian. When it raged for the first time at Con- 

 stantinople (A.D. 542) the mortality was enormous. 

 Ten thousand persons are said to have died in a day 

 with all the symptoms of bubonic plague. 



It spread swiftly through the Roman Empire. In 

 the fourteenth century the same disease under the 

 name of the Black Death again ravaged Europe. 

 Again the mortality was enormous. Millions perished 

 little suspecting that fleas could be connected with 

 their fate. Everywhere popular tradition reported 

 the plague as the most highly contagious of all 

 diseases. 



In the history of science the plague epidemics in 

 Egypt between 1833 and 1845 are of importance, 

 because the disease was, for the first time, seriously 

 studied by skilful French physicians. Some of the 



