THE RELATION OF LIFE TO OTHER FORCES. 317 



only so in appearance, not in reality. Each act of their life is so much 

 expended of the time and work allotted to them; and if, from absence 

 of those surrounding conditions under which alone life is possible, their 

 vitality is stayed for a time, it again proceeds on the renewal of the 

 necessary conditions, from that point which it had already attained. The 

 amount of life to be manifested by any given individual is the same, 

 whether it takes a day or a year for its expenditure. Life may be of 

 course at any moment interrupted altogether by disease and death. But 

 supposing it, in any individual organism, to run its natural course, it will 

 attain but the same goal, whatever be its rate of movement. Decline 

 and death, therefore, are but the natural terminations of life; thev form 

 part of the conditions on whioh vital action begins; they are the end 

 toward which it naturally tends. Death, not by disease or injury, is not 

 so much a violent interruption of the course of life, as the attainment of 

 a distant object which was in view from the commencement. 



In the period of decline, as during growth, life consists in continued 

 manifestations of transformed physical force; and there is of necessity 

 the same series of changes by which the individual, though bit by bit 

 perishing, yet by constant renewal retains its entity. The difference, as 

 has been more than once said, is in the comparative extent of the loss and 

 reproduction. In decline there is not perfect replacement of that which 

 is lost. Kepair becomes less and less perfect. It does not of necessity 

 happen that there is any decrease of the quantity of material added in 

 the place of that which disappears. But although the quantity may not 

 be lessened, and may indeed absolutely increase, it is not perfect as ma- 

 terial for repair, and although there may be no wasting, there is degen- 

 eration. 



No definite period can be assigned as existing between the end of 

 development and the beginning of decline, and chiefly because the two 

 processes go on side by side in different parts of the same organism. The 

 transition as a whole is therefore too gradual for appreciation. But, after 

 some time, all parts alike share in the tendency to degeneration; until 

 at length, being no longer able to subdue external force to vital shape, 

 they die; and the elements of which they are composed simply employ 

 what remnant of power, in the shape of chemical affinity, is still left in 

 them, as a means whereby they may go back to the inorganic world. Of 

 course the same process happens constantly during life; but in death the 

 place of the departing elements is not taken by others. 



Here, then, a sharp boundary line is drawn where one kind of action 

 stops and the other begins; where physical force ceases to be manifested 

 except as physical force, and where no further vital transformation takes 

 place, or can in the body ever do so. -For the notion of death must in- 

 clude the idea of impossibility of revival, as a distinction from that state 

 of what is called "dormant vitality," in which, although there is no life, 



