ORGANIC DEVELOPEMENT. 603 



functions of nutrition ; and we accordingly find 

 that whenever the seed begins to germinate, the 

 first indication of developement is the appear- 

 ance of the part called the plumula, which is a 

 collection of feathery fibres, bursting from the 

 enveloping capsule of the germ, and which, 

 whatever may have been its original position, 

 proceeds immediately to extend itself vertically ; 

 while, at the same time, slender filaments, 

 or radicles, shoot out below to form the roots. 

 Thus early are means provided for the absorp- 

 tion and the aeration of the nutrient matter, 

 which is to constitute the materials for the 

 subsequent growth of the plant, and for the 

 support and protection of the organs by which 

 these processes are to be carried on. But animal 

 vitality, being designed to minister to a higher 

 order of endowments, is placed in subordination 

 to a class of functions, of which there exists no 

 trace in vegetables, namely, those of the nervous 

 system. By attentively watching the earliest 

 dawn of organic formation, in the transparent 

 gelatinous molecule, for example, which, with its 

 three investing pellicles, constitutes the embryo of 

 a bird, (for the eggs of this class of animals best 

 admit of our following this interesting series of 

 changes,) the first opaque object discoverable by 

 the eye is a small dark line, called the primitive 

 trace, formed on the surface of the outermost 

 pellicle. Two ridges then arise, one on each 



