CHAPTER FOURTH. 



OF INTELLIGENCE AND INSTINCT. 



128. BESIDES the material substance of which the body is 

 constructed, there is also an immaterial principle, which, 

 though it eludes detection, is none the less real, and to 

 which we are constantly obliged to recur in considering the 

 phenomena of life. It originates with the body, and is de- 

 veloped with it, while yet it is totally apart from it. The 

 study of this inscrutable principle belongs to one of the 

 highest branches of Philosophy ; and we shall here merely 

 allude to some of its phenomena which elucidate the devel- 

 opment and rank of animals. 



129. The constancy of species is a phenomenon depend- 

 ing on the immaterial nature. Animals, and plants also, 

 produce their kind, generation after generation. We shall 

 hereafter show that all animals may be traced back, in the 

 embryo, to a mere point in the yolk of the egg, bearing 

 no resemblance whatever to the future animal ; anJ no in- 

 spection would enable us to declare with certainty what that 

 animal is to be. But even here an immaterial principle 

 is present, which no external influence can essentially modify, 

 and determines the growth of the future being. The egg of 

 the hen, for instance, cannot be made to produce any other 

 animal than a chicken, and the egg of the codfish produces 

 only the cod. . It may therefore be said with truth, that the 

 chicken and the cod existed in the egg before their formation 

 as such. 



130. PERCEPTION is a faculty springing from this princi- 

 ple, The organs of sense are the instruments for receiving 



