

AMERICAN MUSEUM GUIDE LEAFLETS 


The second pandemic of plague, the Black Death of the Middle 
Ages, originated in Mesopotamia about the middle of the eleventh 
century. In the track of travel and commerce, particularly on the 
route of the returning crusaders, it quickly spread to the West and 
North. It is said that 25,000,000 people, one fourth of the population 
of Europe, perished of plague during the fourteenth century. 
A third pandemic of plague which is still going on at the present 
time (1918) broke out at Yunnan Fu in China in 1871 and attracted 
seneral notice when it reached Hongkong in 1894. From this point 

Fig. 28. MODEL OF CORNER OF RAT-INFESTED DWELLING 
American Museum of Natural History 
the disease made its way to India where it raged unchecked for ten 
years and carried off 6,000,000 people. This time, however, the 
world invasion of the Black Death was to be met by a new defensive 
mechanism, the organized force of scientific research. A Japanese 
bacteriologist, Yersin, discovered the bacillus of plague in 1894 and 
it was soon proved that the disease from which rats were simultane- 
ously suffering (as they had done in the days of Samuel) was the 
same as the human plague. The infection may be more or less 
chronic among the rodents, persisting among them for years as 
52 
