CHAPTER FOURTH. 



OP 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 de- 

 velopment and rank of animals. 



129. The constancy of species is a phenomenon depend- 

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

 duce their kind, generation after generation. We shall 

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

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

 no resemblance whatever to the future animal. But even 

 here, an immaterial principle, which no external influence 

 can prevent or modify, is present, and determines its fu- 

 ture form ; so that the egg of the hen can produce nothing 

 but a chicken, and the egg of the cod-fish produces only the 

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

 and the cod existed in the egg before their formation. 



130. PERCEPTION is a faculty springing from this princi- 



