39 



a pound of 'charcoal would disengage during its 

 combustion. It ought also to be observed, that 

 the carbon in the blood, as being in a liquid state, 

 may possibly produce more heat from its combus- 

 tion, than when in its solid state. AH these cal- 

 culations, however, have so little claim to be re- 

 garded as exact, that they, are made rather with 

 a view to approximate to the truth, than to be 

 rjelied upon as accurate. For my part, I must 

 confess, that if the observations of ALLEN and 

 PEPYS be correct, it will be very difficult to con- 

 ceive how the body can compensate the extraor- 

 dinary consumption of carbon, which, besides 

 what is separated in other places, presupposes at 

 least from 8 to 10 pounds weight of food within 

 the day, which is more, by far, than any person 

 generally consumes. 



Although the changes, which the blood, during 

 respiration, undergoes in the lungs, according to 

 all appearance, resemble those, which are pro- 

 duced in the blood by the air out of the body ; an 

 influence, in this process, has also been ascribed 

 to the nervous, system, without which, it could 

 not take place. DUPUYTREN, in an experi- 

 ment on horses and dogs, divided the eighth 



air , of nerves, near the oesophagus, and 



