DECAY CONSTANT DURING LIFE. 83 
for their replacement by ordinary acts of growth; and that 
even when the body has been so severely injured that the 
organic functions are seriously disturbed for a time (as 
when a Hydra is divided into two or more pieces, § 122), 
the vitality of the individual parts is sufficiently enduring, 
and their reparative powers sufficiently energetic, to enable 
them to reproduce all that is wanting for the completion of 
the organism, and for the renewal of its ordinary actions. 
Among the higher animals, the death of the organism at 
large may be said to take place when the circulation finally 
ceases; since, as we have just seen, every individual part 
must ere long lose its peculiar functional activity, and the 
entire body be subject to decay. 
68. From what has been stated, it will be seen that Life 
cannot be regarded as a condition in which decay is resisted; 
for an incessant decay is taking place in every living organism 
as a necessary condition of its vital activity, being only 
checked when that activity is itself suspended. But it is a 
condition in which, by the wonderful harmony and mutual 
adaptation of the operations of the different parts, the repa¬ 
rative action of the Organic Functions is made to countervail 
the destructive action involved in the exercise of the Animal 
Faculties; whilst the latter, in their turn, serve to furnish 
the conditions requisite for the maintenance of the former. 
So long as all these actions go on with regularity and com¬ 
pleteness, so long the whole body lives; but if any one of the 
more important among them be interrupted, the stoppage of the 
whole is the result. This relation of mutual dependence is most 
intimate in the higher animals ; in which, by the differentia¬ 
tion of the several tissues and organs, and the specialization 
of their functions, the division of labour is carried to its 
greatest extent, so that no part can entirely fulfil the duty of 
any other. On the other hand, it is among those lowest 
forms of animal life, in which there is the greatest multipli¬ 
cation of similar parts, and the greatest diffusion of the same 
endowments amongst them all, that we find the dependence 
of the several parts of the organism upon each other to be 
the slightest, and severe injuries to be tolerated with the 
least general disturbance. 
