PHYSIOLOGY OF LIFE. 79 



from the seed-leaflets, or cotyledons, through the stalk, 

 the leaves, and the calyx, into the perfect flower, the 

 various colours of which seem made for the reflection of 

 light, as the antecedent grade to the burnished scales, 

 and scale-like eyes of the insect. Nevertheless, with all 

 this seeming prodigality of organic power, the whole ten- 

 dency is ad extra, and the life of insects, as electricity in 

 the quadrate, acts chiefly on the superficies of their bodies, 

 to which we may add the negative proof arising from the 

 absence of sensibility. It is well known, that the two 

 halves of a divided insect have continued to perform, or 

 attempt, each their separate functions, the trunkless head 

 feeding with its accustomed voracity, while the headless 

 trunk has exhibited its appropriate excitability to the 

 sexual influence. 



The intropulsive force, that sends the ossification in- 

 ward as to the centre, is reserved for a yet higher step, 

 and this we find embodied in the class of fishes. Even 

 here, however, the process still seems imperfect, and (as 

 it were) initiatory. The skeleton has left the surface, 

 indeed, but the bones approach to the nature of gristle. 

 To feel the truth of this, we need only compare the most 

 perfect bone of a fish with the thigh-bones of the mam- 

 malia, and the distinctness with which the latter manifest 

 the co-presence of the magnetic power in its solid parietes, 

 of the electrical in its branching arteries, and of the 

 third greatest power, viz., the qualitative and interior, 

 in its marrow. The senses of fish are more distinct 

 than those of insects. Thus, the intensity of its sense of 

 smell has been placed beyond doubt, and rises in the ex- 

 tent of its sphere far beyond the irritable sense, or the 



