THE FUNCTIONS OF LIFE. 53 



The notion has long prevailed that the beings 

 composing the vegetable and animal kingdoms, 

 might, if we were thoroughly acquainted with 

 their structure and economy, be arranged in a 

 linear series, commencing with the simplest and 

 regularly ascending to the most refined and com- 

 plicated organizations, till it reached its highest 

 point in man, who is unquestionably placed at 

 the summit of the scale. Bonnet, in particular, 

 cherished with enthusiastic ardour the hypo- 

 thesis that all organic beings formed a con- 

 tinuous gradation, each member of which, like 

 the successive links of a chain, was connected 

 with that which preceded, and with that which 

 followed it; and he pursued this idea by ap- 

 plying it even to the productions of the mineral 

 world. But, divesting ourselves of these hypo- 

 thetical views and figurative images, we find, on 

 sober observation, that instead of one continuous 

 series, we are presented with only detached frag- 

 ments and interrupted portions of this imaginary 

 system : so that, if, for the sake of illustration, we 

 must employ a metaphor, the natural distribution 

 of animals would appear to be represented, not 

 by a chain, but by complicated net-work, where 

 several parallel series are joined by transverse 

 and oblique lines of connexion. A multitude of 

 facts, however, tend to show that the real types 

 or models of structure, are more correctly re- 

 presented by circular or recurring arrange- 



