158 HEREDITY. 



every thing in life by matter and motion. In what 

 we call vitality, he would explain every thing in 

 terms of matter and force. When, however, he gives 

 a definition of what he means by polarity, the facts of 

 actual observation trouble him. He says that there 

 is " an innate tendency in living particles to arrange 

 themselves into the shape of the organism to which 

 they belong .... For this property there is no fit 

 term. If we accept the world ' polarity ' " I am 

 quoting here a chapter enlitled " Waste and Repair," 

 in Spencer's Biology (American edition, pp. 180-183) 

 " as a name for the force by which inorganic units 

 are aggregated into a form peculiar to them, we may 

 apply this word to the analogous force displayed by 

 organic units .... taking care, however, to re- 

 strict its meaning." 



Hundreds of loose readers of Spencer think he 

 means by " polarity " just what is meant by it in the 

 range of physical research. He carefully restricts 

 the meaning of the word, and closes his paragraph 

 by this very significant language: "If we simply 

 substitute the term ' polarity ' for the circuitous ex- 

 pression, the power which certain units have of ar- 

 ranging themselves into a special form, we may, with- 

 out assuming any thing more than is proved, use the 

 term 'organic polarity,' or polarity of the organic 

 units, to signify the proximate cause of the ability 

 which organisms display of reproducing lost parts." 

 Elsewhere he says that this same law is involved in 

 hereditary descent. By organic polarity, therefore, 

 he always means the power that certain units have of 



