LIFE: ITS ORIGIN AND MATURE 
21 
is in some way recharged by energy—fitting 
it for the next day’s work—outward mani¬ 
festations of life are lacking; but even here, 
certain internal mechanisms of the body 
(respiration, digestion, circulation, etc.) are 
active, but at a lower level. Muscular activity 
does not, curiously enough, wear out the parts 
utilized, but, on the contrary, strengthens and 
invigorates them. The more energy we expend 
in this way (within certain limits) the more 
we receive. Life and love are thus to some 
extent analogous; for, in the latter case also, 
“the more freely we give the more freely do we 
receive.” 
Up to a certain point, the activities of life are 
healthful; beyond that point, they become de¬ 
structive. This is very obvious to us in the 
case of muscular activities. When muscles are 
exercised, a greater volume of blood is de¬ 
termined to these parts, which are thus fed, 
while impurities are carried away into the gen¬ 
eral blood-stream. When fatigue has once begun 
to supervene, however, these impurities begin 
to collect at a faster rate than they can be 
eliminated. A fatigued muscle is a poisoned 
muscle. It has been*shown that a muscle may 
be washed-out, by means of salt water, and the 
fatigue removed, so that the muscle is as 
vigorous as ever. There are, however, two 
kinds of fatigue; (1) purely muscular fatigue, 
and (2) nervous exhaustion, which results from 
the depletion of the nervous energies in the 
nerve-cells or centres. 
The most obvious of these manifestations of 
life is, of course, muscular activity, for here 
