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XXVII. Dissertation on the Origin and the uniform Distribu- 
tion of Animal Heat. By Professor Vax Mons, of Lou- 
vain *, 
Tuar union of functions which constitutes animal life can only 
have effect at a certain degree of temperature. These functions 
consist in a suecession of compositions and decompositions, which 
take place according to lawsmodified by the vital influence, whose 
foundation is in ealoric. 
Persons have occasionally remarked, that the temperature of 
their bodies was different from that of the medium in which they 
lived, and they have sought to discover the cause of this differ- 
ence. 
The philosophers of antiquity touched pretty nearly upon this 
cause, when they admitted ‘‘ that by the identification of the air 
with the blood, this liquid becomes improved, and assumes a spi- 
ritous nature, from which result heat and pulsation.” These are 
their own words. 
More recent speculators, either losing sight of these opinions 
of the ancients or interpreting them very badly, have wandered 
much further from the truth, and given themselves up to systems 
more or less absurd; one of the most in vogue of which has been, 
that which attributes the development of animal heat to the fric- 
tion of the blood against the sides of the sanguiferous vessels.— 
These systems having no longer any partisans, do not stand in 
need of refutation. 
It was necessary that modern chemistry should shed its light 
upon the secrets of physiology, in order to give a just idea of the 
mechanism of respiration, and to deduce from it the true origin 
of aniinal heat. 
Mayo and other chemists had perceived a strong analogy be- 
tween the process of combustion and that of respiration ; but it 
was reserved for French chemistry to place the phenomena of this 
last process in its full light. 
The authors of the new theory of respiration believed for a long 
time, that there takes place in the lungs a direct and complete 
combustion of carbon and of the hydrogen of the blood by the 
oxygen gas inspired ; and that the caloric dtéehiragred by that com- 
bustion, after having gasified the carbonic acid, and evaporated 
the water, unites itself to the blood in order to be transferred into 
the circulation and furnish the animal heat. Si 
But on the supposition that matters were thus arranged, the 
cavity of the thorax would have a temperature much superior to 
that of other parts of the body, and would serve in some sort as a 
* Translated from a communication made by the author. 
heating 
