BODILY WORK AND WASTE. 
151 
heat acting upon the atmosphere, in which it produces cur- 
rents ; and that the heat comes from the sun, whose material 
relations exhibit, even to our superficial observation, a state of 
disturbance which is eminently suggestive of a more profound 
and incessant disorganization going on beyond our ken. 
We may, therefore, take it as unquestionable, that so far as 
the inorganic forces of nature are concerned, their manifesta- 
tion in all cases involves the contemporary occurrence of waste, 
decomposition, or decay. But what are we to say of the forces 
which are given off by organized bodies ? This thinking, talk- 
ing, acting machine which we call man, whose brain is con- 
tinually giving off nerve-force, which is as constantly stimulating 
some one or other of his muscles to give off motor or mechanical 
force, and whose whole organism is incessantly maintained by 
the operations of the chemical and 'physiological forces which 
digest his food, convert it into the various tissues of his body, 
and again reconvert those tissues into the simpler forms in 
which, when they have served their part, they are eliminated 
from the system — hence does he obtain all these forces, or, 
more properly speaking, all these different varieties of force, 
which are so indispensable to his existence ? Here, too, we 
must recur for an answer to these questions to the great law of 
the relations of waste and power to which allusion has before 
been made. The human body is continually wearing away ; as 
truly, though perhaps not so evidently, burning away as if it 
were a bushel of coals in a domestic grate. And it is from this 
| ceaseless process of waste which is going on everywhere within 
it, that it derives the power which it expends in the various 
forms of work which it continually carries on. There are pro- 
bably very few of the readers of this article who have the 
faintest idea of the amount of force which they are exerting 
every day of their lives. Let us see if we can manage, without 
! wandering into details whose due appreciation would require a 
knowledge of the more profound departments of physiology, to 
form an estimate of the amount of work which the body of an 
ordinary man performs in the twenty-four hours, and of the 
waste of bodily substance of which that work is the 
equivalent. 
We may roughly divide the constituents of the animal frame 
into three groups. In the first we will place those substances 
which are actually incorporated into its organization in the 
shape of bone, muscle, nerve, &c. ; to the second we may 
assign those which are destined to minister to the building 
i up of the animal fabric, in the shape of the raw materials 
derived from the digestion of the food in the alimentary canal, 
; and, in the third, we shall place those constituents which, 
i having discharged their functions in the animal economy as 
