THEORY OF RESPIRATION. 253 



considered and constantly kept in view, as the ultimate 

 and most powerful cause of a lasting vital resistance, as 

 well in the diseased as in the unaffected parts of the 

 body. 



It is obvious, moreover, that in all diseases where 

 the formation of contagious matter and of exanthemata 

 is accompanied by fever, two diseased conditions simul- 

 taneously exist, and two processes are simultaneously 

 completed ; and that the blood, as it were by reaction 

 (that is, fever), becomes a means of cure, as being the 

 carrier of that substance (oxygen) without the aid of 

 which the diseased products cannot be rendered harm- 

 less, destroyed, or expelled from the body ; a means of 

 cure by which, in short, neutralization or equilibrium is 

 effected. 



IV. 



THEORY OF RESPIRATION. 



During the passage of the venous blood through the 

 lungs, the globules change their color; and with this 

 change of color, oxygen is absorbed from the atmos- 

 phere. Further, for every volume of oxygen absorbed, 

 an equal volume of carbonic acid is, in most cases, 

 given out. 



The red globules contain a compound of iron ; and 

 no other constituent of the body contains iron. 

 22 



