CHAPTER XVI. 



THE LAW OF EVOLUTIOX CONTINUED. 



§ 128. But now, does this generalization express the 

 whole truth? Does it include everything essentially char- 

 acterizing Evolution and exclude everything else? Does 

 it comprehend all the phenomena of secondary re-distribu- 

 tion which Compound Evolution presents, without compre- 

 hending any other phenomena? A critical examination of 

 the facts will show that it does neither. 



Changes from the less heterogeneous to the more hetero- 

 geneous, which do not come within what we call Evolution, 

 occur in every local disease. A portion of the body in which 

 there arises a morbid growth, displays a new differentiation. 

 Whether this morbid growth be, or be not, more hetero- 

 geneous than the tissues in which it is seated, is not the 

 question. The question is, whether the organism as a whole 

 is, or is not, rendered more heterogeneous by the addition 

 of a part unlike every pre-existing part, in form, or com- 

 position, or both. And to this question there can be none 

 but an affirmative answer. Again, it may be con- 



tended that the earlier stages of" decompositon in a dead 

 body involve increase of heterogeneity. Supposing the 

 chemical changes to commence in some parts sooner than in 

 other parts, as they commonly do; and to affect different 

 tissues in different ways, as they must; it seems to be a 

 necessary admission that the entire body, made up of unde- 



composecl parts and parts decomposed in various modes and 



372 



