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 

 upwards ; while, at the same time, slender fila- 

 ments, or radicles, shoot out below to form the 

 roots. Thus early are means provided for the 

 absorption 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 intently watching the earliest dawn 

 of organic formation, in the transparent gelatinous 

 molecule, for example, which, with its three in- 

 vesting 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 



