92 THE MORPHOLOGY 



such expressions as cylindrical, prismatic, circular, spherical 

 and the like, have no longer a well-defined geometrical 

 signification in their application to plants, but merely an 

 approximative, comparative value. 



From these circumstances, it is evident that very general 

 information and a peculiar tact, I might almost say instinct, 

 for natural science, is necessary to the safe advance of a 

 single step forward in the study of the forms of plants, and 

 that here we must, in the very first place, develop special, 

 guiding maxims from the nature of the object itself, 

 according to which to criticise, reject or admit the 

 innumerable possible systems of Vegetable Morphology. 

 This, indeed, gives us but the negative result, that all 

 the rules tending to the rejected systems are useless, while 

 the admitted acquire only a possibility, but no certainty of 

 correctness. Nevertheless, much has already been gained 

 by it, since the investigations become continually more 

 simple. When, guided by such principles, we direct our 

 attention to the plant, it presents two peculiarities, which 

 make good their distinct claim to regard in all our investi- 

 gations. One is the composition of the plant out of little, 

 almost independent and individualized elementary organisms, 

 namely the cells ; the other is the continuous process of 

 absorption and excretion of matter, the production and 

 dissolution of cells, and as a consequence of both, the 

 constant alteration of the internal and external form, the 

 structure and the shape. 



The maxims to be derived from these are : 



" Whatever, in the plant, has not been traced back to 

 its composition from individual cells, is not yet known 

 or understood, consequently cannot be used as the basis 

 of any theoretical considerations." And secondly : 



" No individual, persistent, or rather, apparently per- 



