218 
The Applications of Physiology 
Experiments have taught us that the average quantity of carbon 
in the food of an adult man amounts to 14 ounces daily. T3y the 
combustion of this quantity, 197,477" of heat are produced 
(Liebig) ; and this is amply sufficient to account for the heat of 
the human body. The experiments of Boussingault show, that a 
cow breathes out about 70 ounces of carbon daily, and from this 
we calculate that 987,385° of heat must be produced in the body 
of a cow in the space of twenty-four hours.* These calculations 
will at once prove that there is little difficulty in accounting for 
the heat of the animal body. 
But as the heat of the animal body is the same in all regions, it 
is obvious that the quantity of fuel (food) necessary to sustain the 
constant temperature of the body must vary according to the nature 
of the climate. Thus less food is required for this purpose in 
India, where the temperature of the external air equals that of 
the body, than in the polar regions, in which it is very many 
degrees lower. But a beneficent Providence has arranged the 
produce of different countries so as to meet the exigencies of the 
climate. The fruits, upon which the inhabitants of warm countries 
love to feed, contain only 12 per cent, of carbon, while the train- 
oil enjoyed by the inhabitants of arctic regions contains above 70 
per cent, of the same element. 
"Were we," says Liebig, "to go naked like certain savage 
tribes, or if in hunting and fishing we were exposed to the same 
degree of cold as the Samoyedes, we should be able with ease to 
consume 10 lbs. of flesh, and perhaps a dozen of tallow candles 
into the bargain, as warmly clad travellers have related with 
astonishment of these people. We should then also be able to 
take the same quantity of brandy or train-oil without bad effects, 
because the carbon and hydrogen of these substances would only 
suffice to keep up the equilibrium between the temperature of the 
external air and that of our bodies. "f 
We often wonder how the Greenlander or Russian can relish 
train-oil : we know perfectly that our own organs of digestion 
would refuse to receive it ; but the cases are very different. In 
cold countries the air is much condensed, for you are well aware 
that air expands by heat and contracts by cold. Hence the 
inhabitant of a cold region receives much more oxygen at each 
respiration than the inhabitant of a hot country, in which the air 
is expanded by heat. In a cold country, therefore, more carbon 
is necessary to combine with the excess of oxygen than in the hot 
country. As oxygen never escapes from the system after having 
entered it, except in union either with carbon or with hydrogen, 
* This implies the union of 11 lbs. 10| oz. of oxygen with the carbon, 
t Chemistry applied to Physiology and Pathology. Edited by Dr, 
Gregory. 
