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CONVERSATION XXIII.

ON ANIMAL HEAT; AND ON VARIOUSANIMAL PRODUCTS.

EMILY.

Since our last interview, I have been thinkingmuch of the theory of respiration ; and I cannothelp being struck with the resemblance which itappears to bear to the process of combustion. Forin respiration, as in most cases of combustion, theair suffers a change, and a portion of its oxygencombines with hydrogen and carbone, producingcarbonic acid and water.

MRS. B.

I am much pleased that this idea has occurred toyou : these two processes appear so very analogous,that it has been supposed that a kind of combustionactually takes place in the lungs ; not of the blood,but of the superfluous hydrogen and carbone whichthe oxygen attracts from it.