PROXIMATE CONCEPTION OF LIFE. 87 



spoct of dcfinitcncss. The associated changes going on in a 

 glacier, admit of indefinite variation. Under a conceivable 

 alteration of climate, its thawing and its progression may be 

 stopped for a million years, without disabling it from again 

 displaying these phenomena under appropriate conditions. 

 By a geological convulsion, its motion may be arrested with- 

 out an arrest of its thawing; or by an increase in the in- 

 clination of the surface it slides over, its motion may be 

 accelerated without accelerating its rate of dissolution. 

 Other things remaining the same, a more rapid deposit of 

 snow may cause great increase of bulk; or, conversely, the 

 accretion may entirely cease, and yet all the other actions 

 continue until the mass disappears. Here, then, the combina- 

 tion has none of that definiteness which, in a plant, marks 

 the mutual dependence of respiration, assimilation, and cir- 

 culation; much less has it that definiteness seen in the 

 mutual dependence of the chief animal functions; no one of 

 which can be varied without varying the rest; no one of 

 which can go on unless the rest go on. Moreover, this 

 definiteness of combination distinguishes the changes occur- 

 ring in a living body from those occurring in a dead one. 

 Decomposition exhibits both simultaneous and successive 

 changes, which are to some extent heterogeneous, and in a 

 sense combined; but they are not combined in a definite 

 manner. They vary according as the surrounding medium 

 is air, water, or earth. They alter in nature with the tem- 

 perature. If the local conditions are unlike, they progress 

 differently in different parts of the mass, without mutual 

 influence. They may end in producing gases, or adipocire, 

 or the dry substance of which mummies consist. They may 

 occupy a few days or thousands of years. Thus, neither in 

 their simultaneous nor in their successive changes, do dead 

 bodies display that definiteness of combination which charac- 

 terizes living ones. It is true that in some inferior 

 creatures the cycle of successive changes admits of a certain 



