THEORY OF RESPIRATION. 265 



time ; and the blood must, therefore, be 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 exanthe- 

 mata is accompanied by fever, two diseased condi- 

 tions simultaneously exist, and two processes are 

 simultaneously completed ; and that the blood, as 

 it were by re-action (i. e. fever), becomes a means of 

 cure, as being the carrier of that substance (oxygen) 

 without the aid of which the diseased products can- 

 not be rendered harmless, 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 2)assage of the venous blood through 

 the lungs, the globules change their colour ; and 

 with this change of colour, oxygen is absorbed from 

 the amosphere. Further, for every volume of oxy- 

 gen absorbed, an equal volume of carbonic acid is, 

 in most cases, given out. 



The red globules contain a compotmd of iron ; 

 and no other constituent of the body contains iron. 



Whatever change the other constituents of the 



