VIII.] HOMOLOGIES. 207 



Polarities," strongly supports tlie philosophical importance 

 of these peculiar relations, adding arguments in favour of 

 antero-posterior homologies, which it is here unnecessary 

 to discuss, enough having been said, it is believed, to 

 thoroughly demonstrate the existence of those deep in- 

 ternal relations which are named lateral and serial 

 homolof^ies. 



What explanation can be offered of these phenomena ? 

 To say that they exhibit a " nutritional relation " brought 

 about by a " balancing of forces " is no explanation of the 

 fact. The changes are, of course, brought about by a 

 " nutritional " process, and the symmetry is undoubtedly 

 the result of a " balance of forces," but to say so is a 

 truism. The question is, what is the cause of this " nutri- 

 tional balancim^ " ? It is here contended that this " balan- 

 cing " must be due to an internal cause wliich at present 

 science is utterly incompetent to explain. It is an internal 

 property possessed by each living organic whole as well 

 as by each non-living crystalline mass, and that there is 

 such internal power or tendency, which may be termed a 

 "polarity," seems to be demonstrated by the instances 

 above given, ^vhich can easily be multiplied indefinitely. 

 Mr. H Spencer^ (speaking of the reproduction, by budding, 

 of a Begonia-leaf) recognizes a power of the kind. He says : 

 " We have therefore no alternative"^ but to say, that the 

 living particles composing one of these fragments, have an 

 innate tendency to arrange themselves into the sliape of 

 the organism to which they belong. We must infer that 

 a plant or animal of any species, is made up of special 

 units, in all of which there dwells the intrinsic aptitude 

 to aggregate into the form of that species : just as in the 



^ " Principles of Biology," vol. i p. 180. 



