496 ZOOLOGY 



possess the greatest historical importance. Thus a 

 description of what went on behind the lines may pos- 

 sess more value, may mean more in relation to the 

 future, than one of the heroic acts in battle. From the 

 point of view of general history there is a rather close 

 parallel between wars and epidemics, in that both are 

 destructive, and both necessitate a process of recon- 

 struction during which new tendencies are likely to 

 develop. Both, also, may be so severe and so pro- 

 longed that a sort of historic fatigue sets in, and ade- 

 quate reactions become impossible. Both, again, may 

 select for destruction particular groups of individuals in 

 a mixed population, and thus alter the average quality 

 of the germ plasm of the nation or nations concerned. 

 The Black 9- As an example of the effects of an epidemic, we 

 Death ma y ta k e the history of the Black Death, the great 



plague which devastated Europe in the fourteenth cen- 

 tury. It will readily be seen that it resembles in some 

 of its effects that other great European disaster, the 

 war in our own times. The Black Death or Plague is 

 an Asiatic disease, which has at different times invaded 

 Europe. The last epidemic in England of first-class 

 importance was the Plague of London, shortly after 

 the middle of the seventeenth century. The Black 

 Death of the fourteenth century is said to have de- 

 stroyed half the population in many parts of Europe. 

 F. A. Gasquet, who has given us a vivid account of it, 

 thus describes the reaction of the English in the presence 

 of this great disaster and following it : 



"In dealing with this subject it is difficult to bring 

 home to the mind the vast range of the great calamity, 

 and duly to appreciate how deep was the break with 

 then existing conditions. The plague of 1349 simply 

 shattered them. . . . The tragedy was too grave to 



