18S 
liebig's organic chemistry. 
several examples are adduced, derived from youth and age, 
labor and rest, and difference of climate. 
As one of the incidental results of the combination of carbon 
and hydrogen, the temperature of body, or animal heat, is to 
be considered. Here it is to be noticed, that those parts, only, 
which are supplied with arterial blood (or that which has ab- 
sorbed oxygen) possess a temperature superior to the sur- 
rounding medium. As we find out of the body, that carbon 
cannot unite with oxygen without producing an elevation of 
temperature, and that from a definite weight, the amount 
of caloric is the same, whatever may be the time consumed 
in the effecting the combination, so the same cause in the body 
must produce similar results: and thus, in the slow combus- 
tion of the carbon and hydrogen of the food, or of the or- 
ganism, we have the source of animal heat. If this be the 
fact, then those circumstances which influence the consump- 
tion of oxygen, will also influence the animal temperature, 
and this is found to agree with observation. Animals of 
quick respiration, and who require a large amount of oxygen, 
belong to the class of warm blooded animals, and possess an 
elevated temperature; while those which require but little 
oxygen, (as fish, which only obtain it from the air contained 
in water,) possess a temperature but little above the medium 
in which they live. 
In man, the temperature of the adult is uniform in every 
region of the globe. How does this correspond with the 
amount of oxygen respired, and of carbon received by the 
system ? In the warmer regions of the globe, the natural 
instinct leads to food deficient in carbon, and the atmosphere 
expanded by heat, does not afford as large a supply of oxy- 
gen; while, in the colder, the contrary is exhibited, and 
that food is preferred which affords a large proportion of 
carbon, and the increased density of the atmosphere at the 
same time supplies more oxygen for its combustion — with 
the consequent elimination of a greater abundance of caloric 
to supply that abstracted by the lower temperature of the 
