86 Mr. Burnett on the Development 



very superficial essay ; but rather to illustrate the functional 

 distribution of the vegetable organism, on the principles just 

 now adumbrated, according to the progressive stages of its 

 development : and then to follow out one series or rather one 

 section of one series, leaving other sections and other series of 

 this very extensive inquiry to a future time, as fit topics for 

 subsequent elucidation. 



In the functional distribution of the vegetable organism us, 

 it is found most convenient (it is also thought to be most phi- 

 losophical, i. e. most consistent with natural phenomena) to 

 distinguish the various organs under whatever external modi- 

 fications they may appear, as nutrients and generants, i. e. into 

 the nutritive and reproductive systems, e. g. to associate as 

 nutrients all those organs which tend chiefly to the growth and 

 preservation of the individual ; and as generants all those 

 which are more especially designed to favour the increase and 

 preservation of the specie: but to these two opposite and 

 essential spheres, a third, which is accessary, or intermediate, 

 must be added, viz,, the organ of extension, formed more or 

 less of both extremes, and serving equally for their varied 

 segregation and extension. 



In many of the more highly developed plants the nutritive 

 and reproductive systems are easily distinguishable from each 

 other ; and in many even some of the subordinate parts of each 

 are separable likewise ; thus of the nutritive system the root 

 is the chief organ of absorption, the leaves of respiration, and 

 so on : furthermore it would seem that occasionally one surface 

 of the leaf is the more especial organ of respiration, while the 

 other is that of aqueous transpiration ; and again, with regard 

 to transpiration itself, it would appear that absorption and 

 exhalation are the peculiar functions of separate parts. 



In the simpler forms of vegetable existence, however, these 

 distinctions vanish ; for here one organ performs many func- 

 tions, and the several members elsewhese separate, or separable, 

 become blended together in one uncertain state ; and it is often 

 difficult to say whether the semblance is most that of root, or 

 stock, or stem, for each appears occasionally predominant, and 

 all in turn are equally latent and obscure. What, for instance, 

 is the growth of the tremellae ? what that of many of the con- 



