Food in Relation to Work. 139 
vantage of being readily digested and assimilated. Ni- 
trogenous matters, on the other hand, do not undergo 
complete oxidation in the system, and their full force 
value is accordingly not manifested. A residual body is 
formed which taxes the animal powers to some extent to 
eliminate, while at the commencement extensive diges- 
tive action has to be brought into play to render them 
capable of absorption in the alimentary canal. 
The alimentary principles may be classed under three 
heads, the albuminous bodies, fats, carbo-hydrates 
(starches, sugars, etc.) The force-values of these have 
been determined by FRANKLAND by calculation from the 
number of units of heat given off during combustion with 
oxygen. Expressed in foot-pounds they are as follows : 
Mechanical work equivalent to the oxidation within 
the system of 1 oz. 
6 Foot-pounds. 
■S Albumen ... ... ... ... 418,925 
% Fat (animal) 
-? /'Starch 
S I Cane sugar 
;§ ^ Grape sugar 
785,117 
339,119 
290,188 
284,075 
It is thus seen that the fats possess by far the greatest 
dynamic value, and, did they offer the same facilities 
for digestion that the carbo-hydrates do, would form by 
far the most ecomomical food for the production of mus- 
cular power. Unfortunately, the capacity for the diges- 
tion of fat exists but to a limited extent, and the diges- 
tive troubles which generally supervene on a diet in 
which fat forms a prominent feature preclude its adop- 
tion, save to a small degree, as an article of diet. 
As has been mentioned before, albuminous matters 
such as meat, eggs, etc., tax the system to a considera- 
ble extent as regards digestion and the elimination of 
S i 
