PROXIMATE DEFINITION OF LIFE. 67 



changes they comprise, we discover that they are distinguish- 

 ed by the combination subsisting among their constituent 

 changes. The acts that make up digestion are mutually de- 

 pendent. Those composing a train of reasoning are in close 

 connection. And generally, it is to be remarked of vital 

 changes, that each is made possible by all, and all are affected 

 by each. Respiration, circulation, absorption, secretion^ in 

 their many sub-divisions, are bound up together. Muscular 

 contraction involves chemical change, change of temperature, 

 -and change in the excretions. Active thought influences the 

 operations of the stomach, of the heart, of the kidneys. But we 

 miss this union among inorganic processes. Life-like as may 

 seem the action of a volcano in respect of the heterogeneity 

 of its many simultaneous and successive changes, it is not life- 

 like in respect of their combination. Though the chemical, 

 mechanical, thermal, and electric phenomena exhibited, have 

 some inter-dependence ; yet the emission of stones, mud, lava, 

 flame, ashes, smoke, steam, usually takes place irregularly in 

 quantity, order, intervals, and mode of conjunction. Even 



here, however, it cannot be said that inanimate things pre- 

 sent no parallels to animate ones. A glacier may be instanced 

 as showing nearly as much combination in its changes as a 

 plant of the lowest organization. It is ever growing and 

 ever decaying ; and the rates of its composition and decom- 

 position preserve a tolerably constant ratio. It moves ; and 

 its motion is in immediate dependence on its thawing. It 

 emits a torrent of water, which, in common with its motion, 

 undergoes annual variations, as plants do. During part 

 of the year the surface melts and freezes alternately ; and 

 on these changes are dependent the variations in movement, 

 and in efflux of water. Thus we have growth, decay, changes 

 of temperature, changes of consistence, changes of velocity, 

 changes of excretion, all going on in connexion ; and it may 

 be as truly said of a glacier as of an animal, that by cease- 

 less integration and disintegration it gradually undergoes an 

 entire change of substance without losing its individuality. 



