PERIOD OF IMMATURITY. 389 



creature which is now all prepared to run its 

 course of life alone. We may well wonder that 

 the naked, or half-naked little beings, which a short 

 time ago we beheld in their state of helpless 

 infancy, with heads too heavy for them to support, 

 and limbs which refused their office, so that they 

 tumbled about in pitiable weakness, should it 

 may be in the course of only a fortnight assume 

 the vigour of full growth, and be able to dart 

 through the air with the almost inconceivable 

 swiftness of a meteor, and be even prepared to 

 traverse vast continents and oceans as distant as 

 the equator. " So soon does Nature advance small 

 birds to their rfkucia, or ' state of perfection ; ' 

 while the progressive growth of man and large 

 quadrupeds is slow and tedious!"*" 



It need scarcely, however, be here repeated, that 

 the period of immaturity varies greatly in different 

 species of birds. Some, as we have already 

 remarked, emerge from the shell half matured, if 

 we may so speak, while others long require the 

 attendance of their parents. The latter are, how- 

 ever, the higher classes of birds, and approach 

 more nearly to mammalia; while the others are the 

 lower classes, and approach the reptiles. 

 * White. 



