84 Instinct. 



important agencies and information which they be- 

 queathed to modern chemistry, which certainly 

 would have been far behind its present state had 

 not the transmutation theory kept so many experi- 

 iienters for ages eagerly at work. 



But let us return to the variables in the king- 

 dom of Hfe. In the ^^g of the Robin, we have not 

 only life but we have in consequence of a fixed va- 

 riable, if I may be allowed the expression, that par- 

 ticular species of bird. There was life — that could 

 be understood as a distinct thing — and this life was 

 finally to manifest itself fully in the production of 

 the Robin in distinction from some other kind of 

 bird. 



Not only are the notions of life, and animal life, 

 and bird life, entirely distinct from the specific no- 

 tion of the Robin, but they can all be reached by the 

 inspection of the embryo bird by every person capa- 

 ble of comprehension at all, before the specific char- 

 acters of the Robin would be so marked as to be 

 perceived by the best naturalist in the world who 

 had studied only the adult bird from which the 

 common notion of the word Robin is derived. But 

 the Robin was from the first potentially present in 

 the ^gg. The materials in the ^g'g do not differ, so 

 far as we can see, either in structure or composition, 

 from the materials in many other eggs ; but there 

 is an artificer there such as is found in no other 

 kind of Q,g%. He can build a Robin from the mate- 

 rials and nothing else. This artificer needs a cer- 

 tain degree of heat for his work. The heat may 

 come from the mother bird, from a bird of any 



