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orders, and regarding it ^9er se, . . . should abstractedly be 

 considered as ranking high, or the contrary." This is an ab- 

 straction of which we are hardly capable, — that of determin- 

 ing the rank of an order ^^e?' se. Still our author's ideas are 

 clear and clearly expressed ; the comparison is really between 

 these plants and the ideal plant-type. And what is wanting 

 to make the comparison practical is a settled idea as to what 

 constitutes the highest stjde of plant, and what is the relative 

 importance of deviations from it ; questions too large to be en- 

 tered upon here, if indeed the science is yet ready for their dis- 

 cussion, but which underlie the most important inquiries which 

 good systematic botanists are everywhere tentatively prosecut- 

 ing. Assuming that the conventional definition of perfection 

 in use among zoologists is applicable to the vegetable king- 

 dom, and which argues that a high degree of specification of 

 organs and morphological differentiation of them for the per- 

 formance of the highest functions indicate a high rank, Dr. 

 Hooker ingeniously argues that " Balanoijhorece may in some 

 respects be considered to hold a very high one ; " and the points 

 are presented under seven heads. Now we will not deny that 

 the principles are logically applied in the present case, nor that 

 the considerations of the kind are perhaps as applicable to 

 the vegetable as to the animal kingdom. But we should 

 a priori expect that principles of fundamental importance in 

 the latter could have no sound application to the former ; that 

 even such as relate to functions common to the two, or to 

 structures analogous, would require to be based each upon its 

 own ground. As to morphology, and as to what constitutes 

 perfection of type, we should look to the fundamental differ- 

 ences rather than to the resemblances of the two for our start- 

 ing-point. 



Plants for obvious reasons are constructed on the principle 

 of extension of surface. Concentration or consolidation, wher- 

 ever it occurs in the vegetable kingdom, is a sj^eclal jjrovlsion 

 against some peculiar danger. Animals, on the contrary, are 

 formed on the principle of restriction of surface. As if to 

 withdraw them as much as practicable from the direct action 

 of the external world, their shape is compact, their extent as 



