172 The Evolution Hypothesis. 



this remote point in the history of organisms we are 

 taught to recognize the principle of heredity. Mr. 

 Spencer calls the sum of these individual character- 

 istics " polarity," taking the term from a phenomenon of 

 inorganic matter, " a power of whose nature we know 

 nothing."* Under this term in physics, "a name for 

 something of which we are ignorant a name for a 

 hypothetical property which as much needs explana- 

 tion as that which it is used to explain "[ he covers 

 all these innate tendencies and proclivities. The 

 polarity of the units is the original of the law of 

 heredity. Polarity in physics is the name of an 

 unknown mode of force. What light does the evolu- 

 tionist throw on the dark places of organic history, by 

 clothing with the same robe of mist the unit, which 

 the spell of his imagination has summoned out of the 

 unseen world ? 



Every observer, from the herdsman of Haran on- 

 ward, has known that the offspring derives its char- 

 acteristics from the parent. Is our knowledge of the 

 fact more clear to us when we are told that there are 

 physiological units lying far below the visible, which, 

 if we could see them, would be found to manifest 

 these same characteristics, and of which the bodies 

 of our cattle are built up ? 



But think of the number and variety of hereditary 

 attributes that we must suppose to be stored up in 



Biology, Vol. I., G4. t Ibid., G5. 



