MIGRATION 
is not the case, as many of the animals that retire to sleep, 
store up beforehand a large quantity of food, in case of 
waking up during the winter. 
The temperature has a most important influence over 
the sensitive organs of an animal, which are further stimu- 
lated by electric changes in the atmosphere, and the more 
careful the attention bestowed upon the subject, the more 
must ultimately be revealed to us many of the causes of 
the movements observed in the highly-organized and sen- 
sitive aerial being known to us as a bird ; the changes in 
the state of the atmosphere, its moisture or dryness, its 
electric or non-electric condition, are all indicated by the 
actions of that wonderful creature, which warn us of the 
coming storm, as surely as they indicate the return of 
spring or the approach of winter. 
Bearing in mind that no other animal, however delicately 
or highly organized, can feel these changes, or give evi- 
dences of them, so completely as a bird, which by its 
power of flight can rise from the hot or cold earth and 
fly, at will, to a warm or cold, dry or moist climate, to 
suit its pleasure or necessity ; we may venture to say that 
the great laws of animal distribution are carried on by 
the changed condition of climate and of food, and conse- 
quent suitability. That migration was ordained by an all- 
wise Providence at, and has continued from, the creation, 
a necessity, not only to all animals but to man, is beyond 
a doubt. 
The arrival in spring at the Northern or Arctic regions 
of migratory birds for the purpose of breeding, instils new 
life and carries fresh food to the men and animals that 
have survived through the gloomy winter. Thus, like re- 
suscitation in a single individual, the exciting causes for 
renewed activity are developed. 
Having supplied the wants of the inhabitants of their 
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