INERTIA AS RELATED TO HEREDITY 67 



viz., to disregard the environment. There must be 

 two properties correlated of course, but physio- 

 logically opposite if not antagonistic. Now Haeckel 

 as clearly as possible regards life, as I do, as the 

 resultant of the simultaneous possession of the 

 two complementary tendencies. Once we have 

 assumed the existence of this other fundamental 

 property in protoplasm, a very great deal of the 

 phenomena of heredity and reproduction is 

 explicable. 



Huxley speaks of " the inevitable recurrence to 

 the original type : " * why inevitable ? Because 

 inertial; it is as " inevitable " as that because 

 of momentum the pushed door should swing on, 

 the disturbed rocking-stone oscillate, the express 

 train dash through the obstructions. Functional 

 inertia preserves race-peculiarities, preserves con- 

 stancy of type through very long periods of 

 time. As Professor Huxley has well said,t "Any 

 admissible hypothesis of progressive modification 

 must be compatible with persistence without 

 progression through indefinite periods." Thus the 

 type of certain fishes has been preserved for ages 

 from very early geological times. " No order of 

 fishes is known to be extinct," says Professor 

 Huxley. } According to Professor Ewart the type 

 of " the horse with the Roman nose " is another 



* T.H.Huxley, " Darwiniana : Collected Essays," vol. ii, p. 114. 

 (Macmillan.) 



t Ibid. vol. viii. 1902, p. 304, 

 J Loc. cit. p. 354, 



