EPIZOOTY. 327 



they have been living at some time or other. It 

 sometimes happens that trees of a certain species 

 will perish in a district all in the same season, 

 though no difference between that and other sea- 

 sons can be observed. One year all the specimens 

 of the dark-leaved American beech in the planta- 

 tions of a district in Scotland died simultaneously, 

 while there was no apparent injury to trees of any 

 other kind. Seals have also in some seasons been 

 observed floating dead on the sea in incredible 

 numbers ; and their dead bodies were so thickly 

 strewed on some parts of the north coast of Scot- 

 land and the northern islands that they tainted 

 the air. Many analogous instances of mortality 

 in particular tribes, for which no cause could be, 

 or at least has been assigned, are recorded ; and 

 because nothing is known of the means by which 

 they are produced, those mortalities are, in the 

 case of animals, called EPIZOOTY, that is, " on the 

 life ;" because they, as it were, fall on the life 

 itself, without any apparent derangement of the 

 organization, or other disease of which the symp- 

 toms can be observed. 



But there is also a gradual wasting away of 

 races, with just as little apparent cause ; though 

 that must not be considered as extending to all 

 cases in which tribes diminish in a country. The 

 wolf is now extinct in the British Isles, and the 

 eagle is rare, excepting in the very wildest dis- 

 tricts ; but both of these have been hunted, and 

 besides that, lonely places are their natural haunts. 

 Heath, too, has diminished upon the uplands, and 

 rushes by the swamps ; but that has been before 

 the plough. 



One of the most remarkable instances of gradual 



Ff2 



