ORDER ACCIPITRES. 147 



flourish in succession, at least for the duration of the summer 

 solstice in our hemisphere. 



But at the approach of the autumnal equinox, plants and 

 animals, being more or less exhausted by the vast expenditure 

 of their vital forces in the great work of reproduction, and also 

 by the increased energy with which those vital forces acted in 

 propulsion to the surface, their external functions begin to be 

 enfeebled, and by so much the more as the heat of the sun 

 diminishes. Then these external parts, these vernal produc- 

 tions, cease to receive aliment through the body ; they have, 

 besides, arrived at the full term of their augmentation, and can 

 admit of no further nutriment. They dry up, wither, are de- 

 tached, and fall. Thus is operated, sooner or later, the fall of 

 flowers, leaves, and fruits, and the change of hairs, feathers, 

 horns, epidermis, scales, &c., when animal and vegetable 

 bodies are brought into this sort of autumnal concentration to 

 prepare them for the winter. In the Austral hemisphere, as 

 our winter is its summer, and reciprocally, the periods of molt- 

 ing every year, must be exactly opposite to ours. 



Under the torrid zone, as the sun passes the equinoxial 

 twice a year from one to the other tropic, it produces, in some 

 measure, two summers and two winters, the latter being sea- 

 sons of perpetual rain. It also determines the moulting and 

 reproduction of animals and vegetables twice a year. Orga- 

 nised beings, in consequence of this, live much more rapidly 

 there than elsewhere ; they are continually in a course of pro- 

 duction and destruction. New flowers arise by the side of the 

 fruits ; the new leaf replaces the old and withered ; the bird 

 recommences its amours, and chaunts renewed pleasures by 

 the side of its nestlings of six months before. 



The birds, by their brilliant plumage, at the season of 

 coupling, announce most remarkably the changes of the moult- 

 ing. The females, as we have said before, having pale and 

 dull colours, appear much less to undergo the moulting, the 

 new plumage being not so distinguishable from the old. But 



L 2 



