vii HEREDITY, VARIATION 119 



as to the observations of other naturalists, treats the whole 

 narrative as gross exaggeration or fabrication ; on which the 

 late Professor Alfred Newton remarks, that the critic would 

 probably have been less severe had he known that, 150 years 

 earlier, these pigeons so swarmed and ravaged the colonists' 

 crops near Montreal, that a bishop of his own Church was 

 constrained to exorcise them with holy water as if they had 

 been demons. Professor Newton adds that the rapid and 

 sustained flight of these pigeons is as well established as 

 their former overwhelming abundance, birds having been 

 killed in the State of New York whose crops contained 

 undigested grains of rice that must have been not long 

 before plucked and swallowed in South Carolina or Georgia. 

 The passenger pigeon has several times been shot in Great 

 Britain, and Professor Newton believes that some of these 

 crossed the Atlantic unassisted by man. 



Considering the vast multitudes of these birds in a state 

 of nature, notwithstanding the variety of birds of prey in 

 North America, together with its unequalled powers of flight, 

 it must be classed as one of the finest examples of what 

 Darwin termed " dominant species," and may also be con- 

 sidered as the highest development of the special type of 

 bird-life manifested in the order Columbae or Pigeons ; and 

 it will doubtless, by future generations of bird-lovers, be 

 counted as a blot upon the boasted civilisation of the 

 nineteenth century that, in its mad greed for wealth, it 

 should have so devastated a whole continent as not to leave 

 room in it for the continued existence of such grand and 

 beautiful life-forms as the bison and passenger pigeon. 



Equally remarkable, perhaps, is the Norwegian lemming, 

 a little animal somewhat larger than our short-tailed field- 

 mouse, but with a tail only half an inch long. This creature 

 is always abundant in Lapland and northern Scandinavia, 

 but only extraordinarily so at long intervals, when favourable 

 conditions lead to its almost incredible multiplication. At 

 intervals of from ten to twenty-five years a great army of 

 them appears, which devours every green thing in its path. 

 Great bands descending from the highlands of Lapland and 

 Finland march in parallel lines about 3 feet apart, never 

 turning aside, crossing lakes, and rivers, and even eating 



