64 



THE DATA OF BIOLOGY. 



merous and more marked. So that though organic change 

 is not rigorously distinguished from inorganic change by 

 presenting successive phases — though some inanimate objects, 

 as watches, display phases of change both quick and nu- 

 merous — though all objects are ever undergoing change of 

 some kind, visible or invisible — though there is scarcely any 

 object which does not, in the lapse of time, undergo a con- 

 siderable amount of change that is fairly divisible into phases ; 

 yet, vital change so greatly exceeds other change in its dis- 

 play of varying phases, that we may consider ' this as prac- 

 tically one of its characteristics. Life, then, as thus roughly 

 differentiated, may be regarded as change presenting succes- 

 sive phases ; or otherwise, as a series of changes. And it 

 should be observed, as a fact in harmony with this concep- 

 tion, that the higher the life the more conspicuous the varia- 

 tions. On comparing inferior with superior organisms, these 

 last will be seen to display more rapid changes, or a more 

 lengthened series of them, or both. 



Contemplating afresh our two typical phenomena, we 

 may see that vital change is further distinguished from non- 

 vital change, by being made up of many simultaneous changes. 

 Assimilation is not simply a series of actions, but includes 

 many actions going on together. During mastication the 

 stomach is busy with the food already swallowed ; on which 

 it is both pouring out solvent fluids and expending muscular 

 efforts. While the stomach is still active, the intestines are 

 performing their secretive, contractile, and absorbent func- 

 tions ; and at the same time that one meal is being digested, 

 the nutriment obtained from a previous meal is undergoing 

 that transformation into tissue which constitutes the final act 

 of assimilation. So also is it, in a certain sense, with mental 

 changes. Though the states of consciousness which make up 

 an argument occur in series, yet, as each of these states is 

 complex — implies the simultaneous excitement of those many 

 faculties by which the perception of any object or relation 

 has been effected; it is obvious that each such change in 



