438 UNITY OP DESIGN. 



kingdoms of organic nature, the same general objects are 

 aimed at, and the same general plans are devised for their 

 accomplishment; and, also, that in the execution of those 

 plans similar means and agencies are employed. In each 

 division there prevails a remarkable uniformity in the com- 

 position and properties of their elementary textures, in the 

 nature of their vital powers, in the arrangement of their or- 

 gans, and in the laws of their production and development. 

 The same principle of analogy may be traced, amidst endless 

 modifications of detail, in all the subordinate groups into 

 which each kingdom admits of being subdivided, both in re- 

 spect to the organization and functions of the objects com- 

 prehended in each assemblage, whether we examine the 

 wonders of their mechanical fabric, or study the series of 

 processes by which nutrition, sensation, voluntary motion, 

 and reproduction are effected. To specify all the examples 

 which might be adduced in confirmation of this obvious 

 truth is here unnecessary; for it would be only to repeat the 

 numerous facts already noticed in every chapter of this trea- 

 tise, relative to each natural group of living beings: and it 

 was, indeed, chiefly by the aid of such analogies, that we 

 were enabled to connect and generalize those facts. We 

 have seen that, in constructing each of the divisions so esta- 

 blished, Nature appears to have kept in view a certain defi- 

 nite type, or ideal standard, to which, amidst innumerable 

 modifications, rendered necessary by the varying circum- 

 stances and different destinations of each species, she always 

 shows a decided tendency to conform. It would almost 

 seem as if, in laying the foundations of each organized fab- 

 ric, she had commenced by taking the exact copy of this 

 primitive model; and, in building the superstructure, had 

 allowed herself to depart from the original plan only for the 

 purpose of accommodation to certain specific v and ulterior 

 objects, conformably with the destination of that particular 

 race of created beings. Such, indeed, is the hypothetical 

 principle, which, under the title of unity of composition, 

 has been adopted, and zealously pursued in all its conse- 



