upon Animal Bodies. 15 



entire. Venous blood returns from all parts of the sys- 

 tem charged with carbonated hydrogen. Carbonated 

 hydrogen has a greater affinity for oxygen gas than for 

 the blood. A double decomposition takes place, and 

 water and carbonic acid are formed. 



Particles of water, to be converted into vapour, are said 

 to absorb 405° of caloric, carbon probably much more. 

 Now it is proved, by the experiment with the Guinea-pig 

 related by Crawford, in his Treatise on Animal Heat, 

 that caloric, instead of being absorbed by the lungs, is 

 carried off in the form of carbonic acid gas, and of wa- 

 ter reduced to the state of vapour. 



Carbon and hydrogen do not exist, in our opinion, 

 as gasses in the vessels, but as constituents of the blood, 

 and hence the necessity of the superior action and tem- 

 perature of the lungs, that these may be separated and 

 thrown off from the rest of the blood, upon its arrival 

 at, and circulation in, the minute pulmonary vessels. 

 The loose caloric evolved by the combinations of oxy- 

 gen with carbon to form carbonic acid gas, and with 

 hydrogen to form water, is communicated to the water 

 for its conversion into vapour, and to those portions of 

 the air which are respired unchanged, which are always 

 increased in temperature by having passed into the lungs. 

 According to the experiments of Dr. Hunter, the tem- 

 perature of the lungs is but about 3° above that of the 

 external organs. The increased temperature of the in- 

 ternal parts beyond that of the external is destined to 

 perfect the secretions in the new decompositions and re- 

 combinations of the fluids, observable in glandular se- 



