WASTE AND REPAIR. 181 



the shape 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 apti- 

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

 atoms of a salt, there dwells the intrinsic aptitude to crystal- 

 lize in a particular way. It seems difficult to conceive that 

 this can be so ; but we see that it is so. Groups of units 

 taken from an organism (providing they are of a certain 

 bulk and not much differentiated into special structures) have 

 this power of re-arranging themselves ; and we are thus 

 compelled to recognize the tendency to assume the specific 

 form, as inherent in all parts of the organism. Mani- 



festly too, if we are thus to interpret the reproduction 

 of an organism from one of its amorphous fragments, 

 we must thus interpret the reproduction of any minor 

 portion of an organism by the remainder. When in place 

 of its lost claw, a lobster puts forth from the same spot a 

 cellular mass, which, while increasing in bulk, assumes the 

 form and structure of the original claw ; we can have no 



hesitation in ascribing this result to a plav of forces like 



j. i 



that which moulds the materials contained in a piece of 

 Begonia-leaf into the shape of a young Begonia. In the one 

 case as in the other, the vitalized molecules composing the 

 tissues, show their proclivity towards a particular arrange- 

 ment ; and whether such proclivity is exhibited in repro- 

 ducing the entire form, or in completing it when rendered 

 imperfect, matters not. 



For this property there is no fit term. If we accept the 

 word polarity, 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. But, as above admitted, polarity, as ascribed to atoms, 

 is but a name for something of which we are ignorant a 



o o 



name for a hypothetical property which as much needs ex- 

 planation as that which it is used to explain. Nevertheless, 

 in default of another word, we must employ this : taking 



