SLOW COMBUSTION OF CAKBON IN OXYGEN. 295 



combustible bodies, as hydrogen, sulphur, and phosphorus, 

 such as takes place within the animal body, the name erema- 

 causis (slow combustion) has been lately given ; and the same 

 term is applied to the decay of organic bodies under the influ- 

 ence of oxygen. 



Under this slow combustion within the living body, free 

 sulphur becomes sulphuric acid, free phosphorus becomes 

 phosphoric acid ; and all salts consisting of an oxidised base, 

 with such vegetable acids as the tartaric, the citric, the acetic, 

 pass into carbonates of the same base ; and this last statement 

 indicates an analogy between such slow combustion and the 

 long-known fact that the tartar of wine, or the impure bitar- 

 trate of potassa, is by destructive heat changed into the pure 

 carbonate of potassa, so long known from this circumstance as 

 the " salt of tartar." 



The process of respiration in animals, in so far as it is a 

 chemical operation, is an eremacausis. The energy of a living 

 animal is in proportion to the activity of its respiration. 

 Birds which perform the extraordinary exertion of carrying 

 themselves by the power of their wings through the atmos- 

 phere, have of all animals the most powerful respiration. It 

 is ascertained that in every kind of animal activity, and par- 

 ticularly in the contraction of muscles, the solids concerned 

 lose a portion of their vitality, that portion becoming reduced 

 to inert matter. According to the views recently advocated, 

 the force of muscular action is due to the combustion of a por- 

 tion of the muscle at each contraction ; that is, to the combin- 

 ation of its carbon with the oxygen of the blood, by which 

 carbonic acid is formed. That is to say, the heat so produced 

 is changed into motion, while the animal heat, in so far as 

 muscular motion is its source, is merely that portion of heat 

 which remains over, or is not changed into motion. 



The carbonic acid formed in such animal acts passes into the 



